[Drakelist] L-4B Bias Voltage
All new filter caps and 3 new WW resistors have been replaced during PS update. During preliminary testing, with 244 VAC line voltage input, I measured 84 VDC at the top end of R-11 (5K 7W) instead of the manuals *120 VDC. Double checked everything and still no 120 VDC. What am I overlooking or is this normal? Thanks joe k7mks ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B Power Supply Electyrolytics
Am looking for a source of 330 MFD 450 VDC caps for my L-4B PS. K9SQG's recent post indicated that All Electronics is a supplier however they have no info on that particular item. My L-4B awaits new caps. Any ideas? joe k7mks ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B Power Supply Electyrolytics
That vendor only carries 220 mfd 450 v caps. However, K9SQG does have a limited amount of 330 mfd, 450 volt, 105 deg, caps. 73, Evan -Original Message- From: k7mks k7...@comcast.net To: drakelist drakelist@zerobeat.net Sent: Mon, Jan 20, 2014 1:43 pm Subject: [Drakelist] L-4B Power Supply Electyrolytics Am looking for a source of 330 MFD 450 VDC caps for my L-4B PS. K9SQG's recent post indicated that All Electronics is a supplier however they have no info on that particular item. My L-4B awaits new caps. Any ideas? joe k7mks ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B load capacitor
I acquired the L-4B from ebay. It is in overall good condition but the load variable capacitor does not have enough shaft friction to hold the plates in position. There appears to be an adjustment screw on the back of the capacitor but there is no easy way to access the screw. Does anyone know a way to adjust the shaft friction of this capacitor without pulling the load capacitor and the fan? Thanks for the help ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B load capacitor
Roger, Yes indeed. Merely buy some felt washers, Antique Radio Supply carries them, sometimes hardware stores, or cut your own. Then remove the load capacitor knob, put several of them on the shaft, and then replace the knob. Keep adding more and more until the desired level of friction is obtained. You can also make washers out of felt you can buy at fabric stores, or you can buy felt pads for lamps at the hardware stores. Please keep us posted on your progress. 73, Evan, K9SQG -Original Message- From: Roger Smith kc6...@earthlink.net To: drakelist drakelist@zerobeat.net Sent: Thu, Oct 24, 2013 4:39 pm Subject: [Drakelist] L-4B load capacitor I acquired the L-4B from ebay. It is in overall good condition but the load variable capacitor does not have enough shaft friction to hold the plates in position. There appears to be an adjustment screw on the back of the capacitor but there is no easy way to access the screw. Does anyone know a way to adjust the shaft friction of this capacitor without pulling the load capacitor and the fan? Thanks for the help ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B load capacitor
- Original Message - From: Roger Smith kc6...@earthlink.net To: drakelist@zerobeat.net Sent: Thursday, October 24, 2013 1:38 PM Subject: [Drakelist] L-4B load capacitor I acquired the L-4B from ebay. It is in overall good condition but the load variable capacitor does not have enough shaft friction to hold the plates in position. There appears to be an adjustment screw on the back of the capacitor but there is no easy way to access the screw. Does anyone know a way to adjust the shaft friction of this capacitor without pulling the load capacitor and the fan? Thanks for the help Check to see if there is any end play in the rotor shaft. If there is you will have to adjust the bearing. If the rotor has no play and seems reasonably well centered look at how its connected. Most rotors use some sort of brush contact. This may introduce some friction. If its got oil or grease on it cleaning may increase the holding friction a bit. Otherwise I agree about using felt washers under the knob. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B blower wheel
Unless the bearings are shot on the blower motor, can replace blower wheel with a much better metal one. See http://www.wb4hfn.com/DRAKE/DrakeArticles/L4B-Fan/Drake%20Fan%20Replacement.pdf 73, Paul, W5NTQ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B/L7 Power Supply Rebuilds
A timely question about the L4/L7 bleeder resistors. I recently had an issue with one of my L4PS supplies. It turned out to be a bad cap which I replaced. I'm going to install a Heathkit Shop board eventually but I wanted to get the amp back on line for use in the ARRL CW DX contest. While the supply was open I checked the 50W bleeder resistors and found them both open. I replaced both with new Ohmite resistors. Sunday morning at about 1230Z, one of the new bleeders failed in dramatic fashion by lighting up like a 100W bulb. I quickly swapped in another L4PS and continued on. Last night after the contest I opened up the failed supply to find that the resistors had failed but all other components were all OK (no bad caps, etc.). I replaced the failed bleeder (again) and all was again normal. I'm still quite puzzled as to why this resistor failed in the first place. GL with the project. 73, Stew K3ND From: Dino Papas k...@cox.net To: Mail List - Drake Gear Drake Gear drakelist@zerobeat.net Sent: Saturday, February 18, 2012 2:22 PM Subject: [Drakelist] L-4B/L7 Power Supply Rebuilds I finally bit the bullet yesterday and got around to rebuilding my L-4BPS and L7PS supplies, one with a Heathkit Shop board and the other with the Harbach version. Both procedures went well, with the second going a LOT faster than the first! I will be rebuilding a friend's L-4BPS next week and figured I could minimize the time to do his by working out the bugs doing mine. As my L-4B is my main amp, and based on Evan's note to me a few years ago, I went ahead and changed out the 5K 7W resistor with the 13W version, replaced the 0.82 ohm HV line resistor and the 50K 50W bleeders as a precautionary measure. In the other amp I guess I was just lazy and simply installed only the Harbach board. Now sitting here thinking about it should I go back and just get it over with and replace the resistors in the L7PS? Has anyone ever had a bleeder go bad? Or the others for that matter. Sure, age will wear anything down. Also, the Harbach board doesn't include the diode balancing resistors that Mike's board does...as the original Drake diode strings used 'em what exactly is the difference? Do modern (read that better) diodes still need that protection? I'm just curious. I was pretty impressed that my 32 year old L-4BPS kept going like the Energizer Bunny all these years and I didn't notice any deterioration at all on the bodies of the orange electrolyticsbut, better safe than sorry and I'm looking forward to many more years of reliable operation with both amps. Thoughts? Dino KL0S ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B/L7 Power Supply Rebuilds
Just like most of us...Age :-) 73, Lee -Original Message- From: GALE STEWARD k...@yahoo.com To: Dino Papas k...@cox.net; Mail List - Drake Gear Drake Gear drakelist@zerobeat.net Sent: Mon, Feb 20, 2012 10:30 am Subject: Re: [Drakelist] L-4B/L7 Power Supply Rebuilds A timely question about the L4/L7 bleeder resistors. I recently had an issue with one of my L4PS supplies. It turned out to be a bad cap which I replaced. I'm going to install a Heathkit Shop board eventually but I wanted to get the amp back on line for use in the ARRL CW DX contest. While the supply was open I checked the 50W bleeder resistors and found them both open. I replaced both with new Ohmite resistors. Sunday morning at about 1230Z, one of the new bleeders failed in dramatic fashion by lighting up like a 100W bulb. I quickly swapped in another L4PS and continued on. Last night after the contest I opened up the failed supply to find that the resistors had failed but all other components were all OK (no bad caps, etc.). I replaced the failed bleeder (again) and all was again normal. I'm still quite puzzled as to why this resistor failed in the first place. GL with the project. 73, Stew K3ND From: Dino Papas k...@cox.net To: Mail List - Drake Gear Drake Gear drakelist@zerobeat.net Sent: Saturday, February 18, 2012 2:22 PM Subject: [Drakelist] L-4B/L7 Power Supply Rebuilds I finally bit the bullet yesterday and got around to rebuilding my L-4BPS and L7PS supplies, one with a Heathkit Shop board and the other with the Harbach version. Both procedures went well, with the second going a LOT faster than the first! I will be rebuilding a friend's L-4BPS next week and figured I could minimize the time to do his by working out the bugs doing mine. As my L-4B is my main amp, and based on Evan's note to me a few years ago, I went ahead and changed out the 5K 7W resistor with the 13W version, replaced the 0.82 ohm HV line resistor and the 50K 50W bleeders as a precautionary measure. In the other amp I guess I was just lazy and simply installed only the Harbach board. Now sitting here thinking about it should I go back and just get it over with and replace the resistors in the L7PS? Has anyone ever had a bleeder go bad? Or the others for that matter. Sure, age will wear anything down. Also, the Harbach board doesn't include the diode balancing resistors that Mike's board does...as the original Drake diode strings used 'em what exactly is the difference? Do modern (read that better) diodes still need that protection? I'm just curious. I was pretty impressed that my 32 year old L-4BPS kept going like the Energizer Bunny all these years and I didn't notice any deterioration at all on the bodies of the orange electrolyticsbut, better safe than sorry and I'm looking forward to many more years of reliable operation with both amps. Thoughts? Dino KL0S ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B/L7 Power Supply Rebuilds
Stew, The situation you experienced is disturbing. The failures you experienced are strange from several perspectives. Why? Well, first, assuming that the power supply is wired correctly, it is unusual to have both bleeders open. When one experiences a failure mode of open, the series circuit is open and the other resistor has no potential across it, thus no power is consumed and it can't over heat, over current, etc. Second, it is unusual to have new bleeders fail that soon after installation. When replacing the resistors, inspect the mounts for the resistors. The older style uses long bolts with mica insulators at each end while the newer style uses aluminum triangles. If there is any arcing to ground, that can contribute to a failed resistor/circuit. Same for an old, brittle wire that might be arcing to ground. Contrary to popular belief, the 0.82 ohm protection resistor will NOT protect the supply from itself for the most part, just excessive current in the RF deck and/or a short in the connecting cable. Though unlikely, ensure that the line voltage for the amp is not excessive which can stress all components, especially the tube filaments. Whenever I rebuild supplies, I always use one or two fans on top of the supply for cooling purposes. I use hand selected model numbers for 220 v that will start and run reliably on 110 vac, or two 110 vac fans in series, or two 12 vdc fans in series; ultra quiet and reduction of heat is dramatic. Note too that when one of those bleeders opens, it will sometimes arc for an extended period of time before completely opening. The light and smell are unforgettable. Please check the 5K 7 watt resistor on the underside of the supply to see if it too has failed. Please keep us posted. 73, Evan, K9SQG -Original Message- From: GALE STEWARD k...@yahoo.com To: Dino Papas k...@cox.net; Mail List - Drake Gear Drake Gear drakelist@zerobeat.net Sent: Mon, Feb 20, 2012 10:29 am Subject: Re: [Drakelist] L-4B/L7 Power Supply Rebuilds A timely question about the L4/L7 bleeder resistors. I recently had an issue with one of my L4PS supplies. It turned out to be a bad cap which I replaced. I'm going to install a Heathkit Shop board eventually but I wanted to get the amp back on line for use in the ARRL CW DX contest. While the supply was open I checked the 50W bleeder resistors and found them both open. I replaced both with new Ohmite resistors. Sunday morning at about 1230Z, one of the new bleeders failed in dramatic fashion by lighting up like a 100W bulb. I quickly swapped in another L4PS and continued on. Last night after the contest I opened up the failed supply to find that the resistors had failed but all other components were all OK (no bad caps, etc.). I replaced the failed bleeder (again) and all was again normal. I'm still quite puzzled as to why this resistor failed in the first place. GL with the project. 73, Stew K3ND From: Dino Papas k...@cox.net To: Mail List - Drake Gear Drake Gear drakelist@zerobeat.net Sent: Saturday, February 18, 2012 2:22 PM Subject: [Drakelist] L-4B/L7 Power Supply Rebuilds I finally bit the bullet yesterday and got around to rebuilding my L-4BPS and L7PS supplies, one with a Heathkit Shop board and the other with the Harbach version. Both procedures went well, with the second going a LOT faster than the first! I will be rebuilding a friend's L-4BPS next week and figured I could minimize the time to do his by working out the bugs doing mine. As my L-4B is my main amp, and based on Evan's note to me a few years ago, I went ahead and changed out the 5K 7W resistor with the 13W version, replaced the 0.82 ohm HV line resistor and the 50K 50W bleeders as a precautionary measure. In the other amp I guess I was just lazy and simply installed only the Harbach board. Now sitting here thinking about it should I go back and just get it over with and replace the resistors in the L7PS? Has anyone ever had a bleeder go bad? Or the others for that matter. Sure, age will wear anything down. Also, the Harbach board doesn't include the diode balancing resistors that Mike's board does...as the original Drake diode strings used 'em what exactly is the difference? Do modern (read that better) diodes still need that protection? I'm just curious. I was pretty impressed that my 32 year old L-4BPS kept going like the Energizer Bunny all these years and I didn't notice any deterioration at all on the bodies of the orange electrolyticsbut, better safe than sorry and I'm looking forward to many more years of reliable operation with both amps. Thoughts? Dino KL0S ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http
[Drakelist] L-4B/L7 Power Supply Rebuilds
I finally bit the bullet yesterday and got around to rebuilding my L-4BPS and L7PS supplies, one with a Heathkit Shop board and the other with the Harbach version. Both procedures went well, with the second going a LOT faster than the first! I will be rebuilding a friend's L-4BPS next week and figured I could minimize the time to do his by working out the bugs doing mine. As my L-4B is my main amp, and based on Evan's note to me a few years ago, I went ahead and changed out the 5K 7W resistor with the 13W version, replaced the 0.82 ohm HV line resistor and the 50K 50W bleeders as a precautionary measure. In the other amp I guess I was just lazy and simply installed only the Harbach board. Now sitting here thinking about it should I go back and just get it over with and replace the resistors in the L7PS? Has anyone ever had a bleeder go bad? Or the others for that matter. Sure, age will wear anything down. Also, the Harbach board doesn't include the diode balancing resistors that Mike's board does...as the original Drake diode strings used 'em what exactly is the difference? Do modern (read that better) diodes still need that protection? I'm just curious. I was pretty impressed that my 32 year old L-4BPS kept going like the Energizer Bunny all these years and I didn't notice any deterioration at all on the bodies of the orange electrolyticsbut, better safe than sorry and I'm looking forward to many more years of reliable operation with both amps. Thoughts? Dino KL0S ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B/L7 Power Supply Rebuilds
Dino et. al. Well, let me briefly relate what I have observed and encountered when rebuilding L4, L4B, and L7 power supplies. Your mileage might vary. My experience has been that the supplies I have worked on have had in excess of a 50% failure rate, and maybe another 25% had whitish or light gray regions, typically toward one end, where there has been excessive heating suggesting and impending failure. Having a stock of the resistors on hand, and having the supply apart, it was a quick job to replace the bleederrs for safety and better regulation. Many people have failed bleeders and are totally unaware of it. There is generally better quality control with diodes nowadays compared to decades ago. Still, for as cheap as resistors are, it is a small price to pay for an added measure of protection, can't hurt. There are two schools of thoughts on this topic so one goes with the one that is most appealing. Final note on that 5K 7wt resistor on the underside of the supply, I too replace it during a standard rebuild and use two 10K 10wt resistors in parallel. Unknown to many, when the original opens, it takes out the ALC pot which, for the L4B I haven't seen in 30 except the ones I have in stock. Enjoy those Drakes, the Drake Nets, and our hobby. 73, Evan, K9SQG -Original Message- From: Dino Papas k...@cox.net To: Mail List - Drake Gear Drake Gear drakelist@zerobeat.net Sent: Sat, Feb 18, 2012 2:24 pm Subject: [Drakelist] L-4B/L7 Power Supply Rebuilds I finally bit the bullet yesterday and got around to rebuilding my L-4BPS and L7PS supplies, one with a Heathkit Shop board and the other with the Harbach version. Both procedures went well, with the second going a LOT faster than the first! I will be rebuilding a friend's L-4BPS next week and figured I could minimize the time to do his by working out the bugs doing mine. As my L-4B is my main amp, and based on Evan's note to me a few years ago, I went ahead and changed out the 5K 7W resistor with the 13W version, replaced the 0.82 ohm HV line resistor and the 50K 50W bleeders as a precautionary measure. In the other amp I guess I was just lazy and simply installed only the Harbach board. Now sitting here thinking about it should I go back and just get it over with and replace the resistors in the L7PS? Has anyone ever had a bleeder go bad? Or the others for that matter. Sure, age will wear anything down. Also, the Harbach board doesn't include the diode balancing resistors that Mike's board does...as the original Drake diode strings used 'em what exactly is the difference? Do modern (read that better) diodes still need that protection? I'm just curious. I was pretty impressed that my 32 year old L-4BPS kept going like the Energizer Bunny all these years and I didn't notice any deterioration at all on the bodies of the orange electrolyticsbut, better safe than sorry and I'm looking forward to many more years of reliable operation with both amps. Thoughts? Dino KL0S ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B
Bill, I am a novice at the L4B, but many of the old T4XB's I got at hamfests in the 80's and repaired had been re-tuned for 11 meters instead of 10M. You might check the input tuning and see if that occurred to yours!! Just a thought. 73, Don, WB5HAK___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B
OR, and this is a big OR, is it possible that even though the previous owner had 10m privileges that the amp was a late run version that did not include 10m??? My L-4B was one of those animals and I had to get the 10m input coil kit from Drake then carefully rub off the small dots of gray paint on the front panel that covered the 10m markings thus making it a fully capable all-band amp (at the time anyway). Long shot but you never know! HNY to all! (and you to Don!) 73 - Dino KL0S On Jan012012, at 1218 PM, Don Cunningham wrote: Bill, I am a novice at the L4B, but many of the old T4XB's I got at hamfests in the 80's and repaired had been re-tuned for 11 meters instead of 10M. You might check the input tuning and see if that occurred to yours!! Just a thought. 73, Don, WB5HAK ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B
Good thought, Dino. I didn't think of that one!!! Happy New Year to you and the wife as well. Good to see you in print. 73, Don, WB5HAK___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B
Just purchased a drake l-4b. Connecting to a 220v circuit in shack. Any thoughts on connecting a new wire and plug and cord with a ground to the amp. In other words, connecting a chassis ground to the electrical ground in the circuit. (of course in addition to your station ground).. Thanks, W5DVG Patrick___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B
I am away from the shack, but my 220 set up is with the three wires as per the DRAKE Manual. I went overboard on the outlet and plug - twist type rated way beyond the needed amperage, but it ws in stock! The breaker is rated as per the manual and only serves the L-4B. Kris KM2KM Just purchased a drake l-4b. Connecting to a 220v circuit in shack. Any thoughts on connecting a new wire and plug and cord with a ground to the amp. In other words, connecting a chassis ground to the electrical ground in the circuit. (of course in addition to your station ground).. Thanks, W5DVG Patrick___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B reduced power
Garey, Hi... I was just reading a post you made on reduced drive to the L-4B from the T-4any. You mentioned having the load at 0. Are you talking the T-4any or the L-4B as to the loading on 0...I suspect it is the T-4any. What if we load up the T-4any to a lower power out by putting the loading somewhere in between 0 and the max smoke position?? Are RF attenuators available somewhere? If this is the preferred way to do it? Who know...I might want to use my Alphs 91B with the T-4any? In that case I need 5-30 watts of drive. Thanks, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B reduced power
I have this problem with my vintage AM station, I use a Yaesu FL2100B with a Johnson Viking-II and to lower the drive level I use a coaxual T placing a dummy load on the T and continue the coax to the anplifier. - Original Message - From: drakelist-boun...@zerobeat.net drakelist-boun...@zerobeat.net To: drakelist@zerobeat.net drakelist@zerobeat.net Sent: Tue Apr 26 07:37:31 2011 Subject: [Drakelist] L-4B reduced power Garey, Hi... I was just reading a post you made on reduced drive to the L-4B from the T-4any. You mentioned having the load at 0. Are you talking the T-4any or the L-4B as to the loading on 0...I suspect it is the T-4any. What if we load up the T-4any to a lower power out by putting the loading somewhere in between 0 and the max smoke position?? Are RF attenuators available somewhere? If this is the preferred way to do it? Who know...I might want to use my Alphs 91B with the T-4any? In that case I need 5-30 watts of drive. Thanks, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B reduced power
John, So what is the details of this setup? How much power goes to the amp, with the dummy load in the circuit? My Alpha only need 35 - 40 watts drive to put out 1500. I usually like to run it with 25 watts drive. Also, I don't want to run my L-4B at full throttle either (800-1,000 out) 73, Lee -Original Message- From: John Hudson john.hud...@calema.ca.gov To: 'kc9...@aol.com' kc9...@aol.com; 'drakelist@zerobeat.net' drakelist@zerobeat.net Sent: Tue, Apr 26, 2011 11:24 am Subject: Re: [Drakelist] L-4B reduced power I have this problem with my vintage AM station, I use a Yaesu FL2100B with a Johnson Viking-II and to lower the drive level I use a coaxual T placing a dummy load on the T and continue the coax to the anplifier. - Original Message - From: drakelist-boun...@zerobeat.net drakelist-boun...@zerobeat.net To: drakelist@zerobeat.net drakelist@zerobeat.net Sent: Tue Apr 26 07:37:31 2011 Subject: [Drakelist] L-4B reduced power Garey, Hi... I was just reading a post you made on reduced drive to the L-4B from the T-4any. You mentioned having the load at 0. Are you talking the T-4any or the L-4B as to the loading on 0...I suspect it is the T-4any. What if we load up the T-4any to a lower power out by putting the loading somewhere in between 0 and the max smoke position?? Are RF attenuators available somewhere? If this is the preferred way to do it? Who know...I might want to use my Alphs 91B with the T-4any? In that case I need 5-30 watts of drive. Thanks, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B reduced power
This is just my own experience running a T4x into a KW linear that needed 30W of drive (pair of 4cx300 grid driven) While the T4 loading control will reduce the output, it tends to make the output non-linear from the T4X. It is better, signal quality wise, to tune the load control properly and back off the power using the RF Gain control. In order to keep the gain control in a reasonable range, I used a 3dB attenuator in a small box in between the T4X and the Amp. This was a simple device made up of a TEE network of Ohmite non-inductive resistors. Use the formula for resistive attenuators for values. Very small, monolithic attenuators are now available from the likes of Anaren, and can be mounted on a small heatsink and work beautifully also. Sometimes available on auction for cheap. Still a good idea to use a monitor scope to be certain that everything is running in a linear manner. Loading and mismatch of T4x output and the Amp input can lead to much distortion and be non-apparent by viewing meters. FWIW Curt KU8L kc9...@aol.com wrote: Garey, Hi... I was just reading a post you made on reduced drive to the L-4B from the T-4any. You mentioned having the load at 0. Are you talking the T-4any or the L-4B as to the loading on 0...I suspect it is the T-4any. What if we load up the T-4any to a lower power out by putting the loading somewhere in between 0 and the max smoke position?? Are RF attenuators available somewhere? If this is the preferred way to do it? Who know...I might want to use my Alphs 91B with the T-4any? In that case I need 5-30 watts of drive. Thanks, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B reduced power
Curt - That is yet another way. I'm not sure why using reduced loading would make the output non-linear It's a 'linear' amplifier which implies that it's 'linear' from zero to full output. It may be that one of the lower level stages are distorting, but I'm not sure why they would. Using the Mic GAIN to reduce output is ok, but you begin to run into S/N problems in the AF and BAL MOD stages. Your three dB pad would certainly help in that regard. Of course you always have the 'possibility' that the MIC GAIN gets left too high from barefoot operation or other accident which would probably blow the grids, (but perhaps not.) Obviously the 3 dB pad has to dissipate whatever power is not fed through to the amplifier. Short duty cycle of SSB might help somewhat, but TUNE and even CW could make for a very hot box! Certainly ANY of these arrangements should never be attempted without a scope!! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Curt Nixon wrote: This is just my own experience running a T4x into a KW linear that needed 30W of drive (pair of 4cx300 grid driven) While the T4 loading control will reduce the output, it tends to make the output non-linear from the T4X. It is better, signal quality wise, to tune the load control properly and back off the power using the RF Gain control. In order to keep the gain control in a reasonable range, I used a 3dB attenuator in a small box in between the T4X and the Amp. This was a simple device made up of a TEE network of Ohmite non-inductive resistors. Use the formula for resistive attenuators for values. Very small, monolithic attenuators are now available from the likes of Anaren, and can be mounted on a small heatsink and work beautifully also. Sometimes available on auction for cheap. Still a good idea to use a monitor scope to be certain that everything is running in a linear manner. Loading and mismatch of T4x output and the Amp input can lead to much distortion and be non-apparent by viewing meters. FWIW Curt KU8L kc9...@aol.com wrote: Garey, Hi... I was just reading a post you made on reduced drive to the L-4B from the T-4any. You mentioned having the load at 0. Are you talking the T-4any or the L-4B as to the loading on 0...I suspect it is the T-4any. What if we load up the T-4any to a lower power out by putting the loading somewhere in between 0 and the max smoke position?? Are RF attenuators available somewhere? If this is the preferred way to do it? Who know...I might want to use my Alphs 91B with the T-4any? In that case I need 5-30 watts of drive. Thanks, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B reduced power
This is why I use a 100 watt dummy load, is has the capability to dissipate the heat of 75 watts. - Original Message - From: drakelist-boun...@zerobeat.net drakelist-boun...@zerobeat.net To: drakelist@zerobeat.net drakelist@zerobeat.net Sent: Tue Apr 26 10:59:55 2011 Subject: Re: [Drakelist] L-4B reduced power Curt - That is yet another way. I'm not sure why using reduced loading would make the output non-linear It's a 'linear' amplifier which implies that it's 'linear' from zero to full output. It may be that one of the lower level stages are distorting, but I'm not sure why they would. Using the Mic GAIN to reduce output is ok, but you begin to run into S/N problems in the AF and BAL MOD stages. Your three dB pad would certainly help in that regard. Of course you always have the 'possibility' that the MIC GAIN gets left too high from barefoot operation or other accident which would probably blow the grids, (but perhaps not.) Obviously the 3 dB pad has to dissipate whatever power is not fed through to the amplifier. Short duty cycle of SSB might help somewhat, but TUNE and even CW could make for a very hot box! Certainly ANY of these arrangements should never be attempted without a scope!! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Curt Nixon wrote: This is just my own experience running a T4x into a KW linear that needed 30W of drive (pair of 4cx300 grid driven) While the T4 loading control will reduce the output, it tends to make the output non-linear from the T4X. It is better, signal quality wise, to tune the load control properly and back off the power using the RF Gain control. In order to keep the gain control in a reasonable range, I used a 3dB attenuator in a small box in between the T4X and the Amp. This was a simple device made up of a TEE network of Ohmite non-inductive resistors. Use the formula for resistive attenuators for values. Very small, monolithic attenuators are now available from the likes of Anaren, and can be mounted on a small heatsink and work beautifully also. Sometimes available on auction for cheap. Still a good idea to use a monitor scope to be certain that everything is running in a linear manner. Loading and mismatch of T4x output and the Amp input can lead to much distortion and be non-apparent by viewing meters. FWIW Curt KU8L kc9...@aol.com wrote: Garey, Hi... I was just reading a post you made on reduced drive to the L-4B from the T-4any. You mentioned having the load at 0. Are you talking the T-4any or the L-4B as to the loading on 0...I suspect it is the T-4any. What if we load up the T-4any to a lower power out by putting the loading somewhere in between 0 and the max smoke position?? Are RF attenuators available somewhere? If this is the preferred way to do it? Who know...I might want to use my Alphs 91B with the T-4any? In that case I need 5-30 watts of drive. Thanks, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B reduced power
That's ok, but the transmitter is also loading into a 25 ohm load, or 2:1 SWR. Not that that is particularly bad, but it might limit the transmitter capability. Have you ever used a scope to see what the signal looks like? I know several people who have used this method, but none have ever really evaluated the signal quality. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com John Hudson wrote: This is why I use a 100 watt dummy load, is has the capability to dissipate the heat of 75 watts. - Original Message - From: drakelist-boun...@zerobeat.netdrakelist-boun...@zerobeat.net To: drakelist@zerobeat.netdrakelist@zerobeat.net Sent: Tue Apr 26 10:59:55 2011 Subject: Re: [Drakelist] L-4B reduced power Curt - That is yet another way. I'm not sure why using reduced loading would make the output non-linear It's a 'linear' amplifier which implies that it's 'linear' from zero to full output. It may be that one of the lower level stages are distorting, but I'm not sure why they would. Using the Mic GAIN to reduce output is ok, but you begin to run into S/N problems in the AF and BAL MOD stages. Your three dB pad would certainly help in that regard. Of course you always have the 'possibility' that the MIC GAIN gets left too high from barefoot operation or other accident which would probably blow the grids, (but perhaps not.) Obviously the 3 dB pad has to dissipate whatever power is not fed through to the amplifier. Short duty cycle of SSB might help somewhat, but TUNE and even CW could make for a very hot box! Certainly ANY of these arrangements should never be attempted without a scope!! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Curt Nixon wrote: This is just my own experience running a T4x into a KW linear that needed 30W of drive (pair of 4cx300 grid driven) While the T4 loading control will reduce the output, it tends to make the output non-linear from the T4X. It is better, signal quality wise, to tune the load control properly and back off the power using the RF Gain control. In order to keep the gain control in a reasonable range, I used a 3dB attenuator in a small box in between the T4X and the Amp. This was a simple device made up of a TEE network of Ohmite non-inductive resistors. Use the formula for resistive attenuators for values. Very small, monolithic attenuators are now available from the likes of Anaren, and can be mounted on a small heatsink and work beautifully also. Sometimes available on auction for cheap. Still a good idea to use a monitor scope to be certain that everything is running in a linear manner. Loading and mismatch of T4x output and the Amp input can lead to much distortion and be non-apparent by viewing meters. FWIW Curt KU8L kc9...@aol.com wrote: Garey, Hi... I was just reading a post you made on reduced drive to the L-4B from the T-4any. You mentioned having the load at 0. Are you talking the T-4any or the L-4B as to the loading on 0...I suspect it is the T-4any. What if we load up the T-4any to a lower power out by putting the loading somewhere in between 0 and the max smoke position?? Are RF attenuators available somewhere? If this is the preferred way to do it? Who know...I might want to use my Alphs 91B with the T-4any? In that case I need 5-30 watts of drive. Thanks, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B reduced power
I always attributed the non-linearity to mismatch issues. As soon as impedance mismatch is present, the output can become distorted. Also, when speaking of using a scope on the output, you can't just monitor the amplitude envelope, you need to be looking at the trapezoid. When the loading is off of the optimum (which happens to be the point of maximum output) the sides of the trap become curved. Sucked in if you will. Or bulging out. Getting down to 50 W using the RF gain control isn't too big an issue with S/N but going down to 10-30 is. Thus the 50 ohm attenuator. THe Anaren 100W monolithic units are about 3/4 x 1/2 and must be mounted on a faily substantial heat sink. I use one mounted to an old CPU finned unit with fan but never really need the fan for CW or SSB. I used one to run the TR7 down to below 1W for a QRP WAS contest in January. Hardly gets warm. THe one for the amp, with resistors, is in a box 4x4x3 and unless you run AM or extended RTTY, the resistors don't have to be capable of anywhere near the full difference in power. Bite the bullet and do it the proper way--use a 50 ohm attenuator. FWIW Curt KU8L Garey Barrell wrote: That's ok, but the transmitter is also loading into a 25 ohm load, or 2:1 SWR. Not that that is particularly bad, but it might limit the transmitter capability. Have you ever used a scope to see what the signal looks like? I know several people who have used this method, but none have ever really evaluated the signal quality. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com John Hudson wrote: This is why I use a 100 watt dummy load, is has the capability to dissipate the heat of 75 watts. - Original Message - From: drakelist-boun...@zerobeat.netdrakelist-boun...@zerobeat.net To: drakelist@zerobeat.netdrakelist@zerobeat.net Sent: Tue Apr 26 10:59:55 2011 Subject: Re: [Drakelist] L-4B reduced power Curt - That is yet another way. I'm not sure why using reduced loading would make the output non-linear It's a 'linear' amplifier which implies that it's 'linear' from zero to full output. It may be that one of the lower level stages are distorting, but I'm not sure why they would. Using the Mic GAIN to reduce output is ok, but you begin to run into S/N problems in the AF and BAL MOD stages. Your three dB pad would certainly help in that regard. Of course you always have the 'possibility' that the MIC GAIN gets left too high from barefoot operation or other accident which would probably blow the grids, (but perhaps not.) Obviously the 3 dB pad has to dissipate whatever power is not fed through to the amplifier. Short duty cycle of SSB might help somewhat, but TUNE and even CW could make for a very hot box! Certainly ANY of these arrangements should never be attempted without a scope!! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Curt Nixon wrote: This is just my own experience running a T4x into a KW linear that needed 30W of drive (pair of 4cx300 grid driven) While the T4 loading control will reduce the output, it tends to make the output non-linear from the T4X. It is better, signal quality wise, to tune the load control properly and back off the power using the RF Gain control. In order to keep the gain control in a reasonable range, I used a 3dB attenuator in a small box in between the T4X and the Amp. This was a simple device made up of a TEE network of Ohmite non-inductive resistors. Use the formula for resistive attenuators for values. Very small, monolithic attenuators are now available from the likes of Anaren, and can be mounted on a small heatsink and work beautifully also. Sometimes available on auction for cheap. Still a good idea to use a monitor scope to be certain that everything is running in a linear manner. Loading and mismatch of T4x output and the Amp input can lead to much distortion and be non-apparent by viewing meters. FWIW Curt KU8L kc9...@aol.com wrote: Garey, Hi... I was just reading a post you made on reduced drive to the L-4B from the T-4any. You mentioned having the load at 0. Are you talking the T-4any or the L-4B as to the loading on 0...I suspect it is the T-4any. What if we load up the T-4any to a lower power out by putting the loading somewhere in between 0 and the max smoke position?? Are RF attenuators available somewhere? If this is the preferred way to do it? Who know...I might want to use my Alphs 91B with the T-4any? In that case I need 5-30 watts of drive. Thanks, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B Repair near Orlamdo, Florida
Hello friends, My buddy lives in Orlando and needs to locate someone to repair his L-4B - anyone nearby or know of someone within driving distance? He's found a short from grid to filament in both 3-500Zs, and with the high voltage disconnected and the tubes removed, the breakers activate after 2-3 seconds. Strange one, huh? Grant Sent from my iPad ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B PS rebuild
Hi Lee, Like you are planning to do, I recently rebuilt an L-4PS that had been sitting idle for about 15 years. I used the Heathkit Ship kit and had excellent success. At the time I installed the Heathkit Shop board, I also replaced R-11, but not R-9 and R-10 as they looked in good condition. Within a month after installing the Heathkit Shop board, R-9 opened. I attribute this to age of R-9 and the new higher voltage from the Heathkit Shop board. My recommendation is to replace R-9 and R-10 and R-11 while you are working on the L-4PS. Good luck. You will have a wonderful amp when you are finished. 73, Tom, W1CC On Sat, Feb 19, 2011 at 8:28 PM, kc9...@aol.com wrote: Hi, Question please. I am rebuilding my L-4B power supply. I have the new Heathkit shop board ready to install. I looked at the 2 bleeders R-9 R-10. They look perfect and measure 50K each. No sign of any issues. Also the bias R-11 looks good and measures 5K. And R-12 .82 ohm special HV resistor looks measure fine. What is the opinion on replacng anything in the L-4B PS besides the Heathkt Shop L-4PSR board? How about in the L-4B iself? The L-4B was working 3 years ago when I set it aside. Thanks, 73, Lee, KC9CDT ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist -- Please note the new email address: tom.del...@gmail.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B PS rebuild
Hi, Question please. I am rebuilding my L-4B power supply. I have the new Heathkit shop board ready to install. I looked at the 2 bleeders R-9 R-10. They look perfect and measure 50K each. No sign of any issues. Also the bias R-11 looks good and measures 5K. And R-12 .82 ohm special HV resistor looks measure fine. What is the opinion on replacng anything in the L-4B PS besides the Heathkt Shop L-4PSR board? How about in the L-4B iself? The L-4B was working 3 years ago when I set it aside. Thanks, 73, Lee, KC9CDT ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B Plate Tuning Cap Question
Dennis - I don't know if it's gonna work but I have a couple of vernier drives that I got from MFJ in anticipation of building some receiver projects. The drive is a 6:1 unitafter I rebuild my supply I'm going to take the amp apart and see if this drive will work. Will report back once I do it but perhaps someone has already done such a repair and can let us know. Dino On Jan132011, at 11:07 PM, Dennis Monticelli wrote: Is there a new replacement drive for the L4B and L7 verniers that can be purchased? Dennis AE6C ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B Plate Tuning Cap Question
They are slightly different for the two amps. However, I have bought replacements that are either direct replacements or ones that need slight modification from Surplus Sales of Nebraska, sometimes Nationwide Radio has them, the Crystal Set Society, and sometimes on Upay, I mean Ebay. 73, Evan, K9SQG -Original Message- From: Dennis Monticelli dennis.montice...@gmail.com To: K9sqg k9...@aol.com Cc: k...@cox.net; drakelist@zerobeat.net Sent: Thu, Jan 13, 2011 11:07 pm Subject: Re: [Drakelist] L-4B Plate Tuning Cap Question Is there a new replacement drive for the L4B and L7 verniers that can be purchased? Dennis AE6C On Thu, Jan 13, 2011 at 2:05 PM, K9sqg k9...@aol.com wrote: Dino, This is normal operation for a vernier drive that has either sat for an extended period of time unused or, in less frequent cases, one that has had a lot of use. There are ways of cleaning, relubing, and then repositioning things so the drive has renewed bite so to speak. However, for all it takes to do this in terms of time and effort, one can consider just replacing the drive itself. It is a matter of personal preference. Good luck with your decision. 73, Evan -Original Message- From: Dino Papas k...@cox.net To: Mail List - Drake Gear Drake Gear drakelist@zerobeat.net Sent: Thu, Jan 13, 2011 3:59 pm Subject: [Drakelist] L-4B Plate Tuning Cap Question Well, today in anticipation of rebuilding my L-4BPS I decided to finally install the Harbach soft-start module in the amp (hey, its only been sitting in the project queue for a few yearsno sense in rushing). While I had it open did the normal maintenance stuff, lubed the fan etc. I've had a problem now for a couple of months with the plate tuning cap turning action. Somewhere between the 80m and 40m sections the turning action slows down to a standstill and you'd have to spin the knob several times to get it to move VERY slowly thru its rotation. With the amp opened up I found that a little bit of pressure applied either as a push or pull would get the cap to rotate at almost normal speed throughout its rotation. Not wanting to screw something up I decided to leave it alone and check with the group. It may just be that after 32 years the rotation mechanism is just wearing out. Anyone else experience this? If so any fixes? Thanks in advance! Dino KL0S BTW, the Harbach module works greatthe power supply board is built and ready to install but think I've done enough for today! ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist = ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B Plate Tuning Cap Question
Is there a new replacement drive for the L4B and L7 verniers that can be purchased? Dennis AE6C On Thu, Jan 13, 2011 at 2:05 PM, K9sqg k9...@aol.com wrote: Dino, This is normal operation for a vernier drive that has either sat for an extended period of time unused or, in less frequent cases, one that has had a lot of use. There are ways of cleaning, relubing, and then repositioning things so the drive has renewed bite so to speak. However, for all it takes to do this in terms of time and effort, one can consider just replacing the drive itself. It is a matter of personal preference. Good luck with your decision. 73, Evan -Original Message- From: Dino Papas k...@cox.net To: Mail List - Drake Gear Drake Gear drakelist@zerobeat.net Sent: Thu, Jan 13, 2011 3:59 pm Subject: [Drakelist] L-4B Plate Tuning Cap Question Well, today in anticipation of rebuilding my L-4BPS I decided to finally install the Harbach soft-start module in the amp (hey, its only been sitting in the project queue for a few yearsno sense in rushing). While I had it open did the normal maintenance stuff, lubed the fan etc. I've had a problem now for a couple of months with the plate tuning cap turning action. Somewhere between the 80m and 40m sections the turning action slows down to a standstill and you'd have to spin the knob several times to get it to move VERY slowly thru its rotation. With the amp opened up I found that a little bit of pressure applied either as a push or pull would get the cap to rotate at almost normal speed throughout its rotation. Not wanting to screw something up I decided to leave it alone and check with the group. It may just be that after 32 years the rotation mechanism is just wearing out. Anyone else experience this? If so any fixes? Thanks in advance! Dino KL0S BTW, the Harbach module works greatthe power supply board is built and ready to install but think I've done enough for today! ___ Drakelist mailing listDrakelist@zerobeat.nethttp://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B Part Needed
Hi Everyone, I know I am looking for a needle in a haystack, but here goes. I need a complete fan motor, blower wheel and mounting brackets for an L-4B amp I am working on restoring. When I got it, it was kludged with some kind of muffin fan. Any help would be appreciated. Thanks, Jeff ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B Blower
Hi All, Thanks for the information on the blower replacements and the auction. Jeff ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B/L-7 Power Switch Potential Replacement
Guys - I know we've batted this issue around a lot and I'm always on the lookout for a source of the unobtainium power switches for our amps. I feel fortunate that I had a spare set to replace my switches and then was able to refurbish the set removed for future use. Recently I found an ad at: https://www.surpluscenter.com/home.asp that included what could be a potential replacement switch. As I don't need them myself I thought I'd let folks know about this source and perhaps someone can do some further investigating and report back to the group. The switch I found is on page 30 of the Surplus Center's catalog supplement which can be downloaded at: https://www.surpluscenter.com/catreq.asp It may take some effort to make it work if it will work at all, but hey at only $1.49, well you never know. Anyway, am hoping this pans out for the guys who need a replacement source. GL - Dino KL0S ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B Power Switch
Question for the group: to address the power surge issue and the vulnerable power switch issue, I bought an Ameritron ARB-704 rated 240v. Until it arrived I didn't know it is also rated 10A. The L-4B takes 15. Any way to bulk up the unit to 15A? Sent from my Verizon Wireless BlackBerry ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B PS Resistor
Anyone have a part number or source for the .82 ohm/2 watt resistor in the power supply? Tried to find it in Mouser catalog - no joy! Thanks, Wayne___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B plug
Hi all, thanks. I'm clear on the need to change the jumpers on the PS and the RF deck (done that before). This sounds just like the 120v plug wiring. RE: the comment about being surprised about what you can find under the chassis in ham gear, that's sure true! regards, Peter___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B follow-up
Just a note, I would be very care full running the L4B on 110V. Look at the manual, I believe Drake recommended not more than a 10 foot length cord to the wall outlet and a number 10 wire for the cord. 73 Tim wb8uhz From: Ron Baker wb4...@comcast.net To: Peter Alterman w2...@live.com; drakelist@zerobeat.net Sent: Sat, August 28, 2010 7:17:18 PM Subject: Re: [Drakelist] L-4B follow-up Peter, from what I can see, from your results the drive power vs. your power output I would say is about what you should expect. Remember running the L4B on 120V the amplifier will not be as efficient as running on 220V.Also, running the amplifier on a standard 120V, 15A house circuit is not near what the amp requires. The specification for the L4B running on 120V requires a 30A circuit minimum. So when you are running the amp on a standard house circuit the primary voltage is probably dropping down to something much less than 120V. That is why I say from the measurements you indicated using a 120V house circuit, the results are about what I would expect to get. For maximum efficiently of the L4B it should be run from a 220V 30A dedicated circuit. Also you drive level should be closer to 100 watts drive.Under that condition, I would expect an output ranging around 1200 watts on 80 meters to 1000 watts on 10 meters.If you need to drive the tubes harder to get the output level the tubes may have become weak over time with use. Try your L4B on 220V on a dedicated 30A circuit, I think you will see a world of difference. Ron / WB4HFN -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Peter Alterman Sent: Saturday, August 28, 2010 5:08 PM To: drakelist@zerobeat.net Subject: [Drakelist] L-4B follow-up Hello Fellow Drake Fans, To recap: The wattmeter on my Palstar AT1500DT reports that I'm getting variable output from my L-4B on dedicated 120v house circuit. On 40 it looks like 800-900 watts out, but on 15 maybe 500. The matched 3-500Zs are about 5 years old, the power supply was rebuilt from kit (Evan may even remember my plaintive cries for help) and I keep a muffin fan over the power supply sucking warm air out. So I promised to do some testing and report back. Here's what I found. First, the setup: Yaesu FT-1000MP Mark V via RG-8X to Drake L-4B L-4B output via RG-213/U to Palstar AT1500DT Output via RG-213/U to Balun Designs 1:1 choke balun (unun) 5 kW model 1115du to Heath Cantenna via RG-8/U patch cable 10+ minute warmup 2600 volts key up in SSB mode 120v AC on a dedicated 15a. circuit Grid current @ 200ma. The results: Band Freqest.drive volts/keydn ma/keydn meter on usual antenna 80 3545.41 40w2250 520 800w 700w 40 7012.54 72w2250 520 800w 900w 20 14063.85 68w2250 520 700w 600w 15 21045.28 70w2250 550 700w 500w 10 28045.11 80w2200 620* 600w 450w Caveats: The Cantenna is by no means the best dummy load but it worked. I have no idea whether the Palstarwattmeter is anywhere near calibrated and it may be frequency-sensitive. Have no idea how accurate the L-4B meters are, but the voltage readings seem to be spot-on, e.g., 1700v in CW/Tune and 2600v in SSB modes. Notes and Observations: 1. Regardless of the accuracy of the Palstarwattmeter, I WAS cranking up the RF power knob on the Yaesu, so I am sure the variation in required input drive is real, though the actual readings are open to question. 2. Also, I only allowed the amp to draw 620 mils on 10 for a few seconds, for test purposes, to keep the drive @ 200 grid mils common. When I backed the drive down to 550 ma on the plate on 10, the grid showed 160 ma. and the wattmeter read 500w. 3. The higher the frequency, the more a minor SWR imbalance showed on the Palstar meter, though never more than 1:1-1. I suspect that this means the Cantenna is not a perfect 50 ohm resistive load; but then, we knew that. 4. The output readings on the dummy load differ sufficiently from what they are with my antennas connected (see above) that it suggests I could do well by doing some work on the transmission lines, coax switch, etc. Nevertheless, something seems to be sub-optimal with the L-4B. It may be time to do some work on the RF deck. The question is, what? Your thoughts and wisdom most welcome, Peter W2CDO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B follow-up
On Sat, 28 Aug 2010 23:42:43 -0400, Garey Barrell wrote: UNLESS the resistor element has been overloaded and/or damaged by certain types of oil coolant and is no longer 50 ohms. I kinda thought that went without saying. :) The oil level should be above the top of the resistor element, or it WILL smoke with high power. Don't ask me how I know this. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime. HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim.exofire.net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B follow-up
Hello Fellow Drake Fans, To recap: The wattmeter on my Palstar AT1500DT reports that I'm getting variable output from my L-4B on dedicated 120v house circuit. On 40 it looks like 800-900 watts out, but on 15 maybe 500. The matched 3-500Zs are about 5 years old, the power supply was rebuilt from kit (Evan may even remember my plaintive cries for help) and I keep a muffin fan over the power supply sucking warm air out. So I promised to do some testing and report back. Here's what I found. First, the setup: Yaesu FT-1000MP Mark V via RG-8X to Drake L-4B L-4B output via RG-213/U to Palstar AT1500DT Output via RG-213/U to Balun Designs 1:1 choke balun (unun) 5 kW model 1115du to Heath Cantenna via RG-8/U patch cable 10+ minute warmup 2600 volts key up in SSB mode 120v AC on a dedicated 15a. circuit Grid current @ 200ma. The results: Band Freqest.drive volts/keydn ma/keydn meter on usual antenna 80 3545.41 40w2250 520 800w700w 40 7012.54 72w2250 520 800w900w 20 14063.85 68w2250 520 700w600w 15 21045.28 70w2250 550 700w500w 10 28045.11 80w2200 620* 600w450w Caveats: The Cantenna is by no means the best dummy load but it worked. I have no idea whether the Palstar wattmeter is anywhere near calibrated and it may be frequency-sensitive. Have no idea how accurate the L-4B meters are, but the voltage readings seem to be spot-on, e.g., 1700v in CW/Tune and 2600v in SSB modes. Notes and Observations: 1. Regardless of the accuracy of the Palstar wattmeter, I WAS cranking up the RF power knob on the Yaesu, so I am sure the variation in required input drive is real, though the actual readings are open to question. 2. Also, I only allowed the amp to draw 620 mils on 10 for a few seconds, for test purposes, to keep the drive @ 200 grid mils common. When I backed the drive down to 550 ma on the plate on 10, the grid showed 160 ma. and the wattmeter read 500w. 3. The higher the frequency, the more a minor SWR imbalance showed on the Palstar meter, though never more than 1:1-1. I suspect that this means the Cantenna is not a perfect 50 ohm resistive load; but then, we knew that. 4. The output readings on the dummy load differ sufficiently from what they are with my antennas connected (see above) that it suggests I could do well by doing some work on the transmission lines, coax switch, etc. Nevertheless, something seems to be sub-optimal with the L-4B. It may be time to do some work on the RF deck. The question is, what? Your thoughts and wisdom most welcome, Peter W2CDO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B follow-up
Peter, from what I can see, from your results the drive power vs. your power output I would say is about what you should expect. Remember running the L4B on 120V the amplifier will not be as efficient as running on 220V.Also, running the amplifier on a standard 120V, 15A house circuit is not near what the amp requires. The specification for the L4B running on 120V requires a 30A circuit minimum. So when you are running the amp on a standard house circuit the primary voltage is probably dropping down to something much less than 120V. That is why I say from the measurements you indicated using a 120V house circuit, the results are about what I would expect to get. For maximum efficiently of the L4B it should be run from a 220V 30A dedicated circuit. Also you drive level should be closer to 100 watts drive.Under that condition, I would expect an output ranging around 1200 watts on 80 meters to 1000 watts on 10 meters.If you need to drive the tubes harder to get the output level the tubes may have become weak over time with use. Try your L4B on 220V on a dedicated 30A circuit, I think you will see a world of difference. Ron / WB4HFN -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Peter Alterman Sent: Saturday, August 28, 2010 5:08 PM To: drakelist@zerobeat.net Subject: [Drakelist] L-4B follow-up Hello Fellow Drake Fans, To recap: The wattmeter on my Palstar AT1500DT reports that I'm getting variable output from my L-4B on dedicated 120v house circuit. On 40 it looks like 800-900 watts out, but on 15 maybe 500. The matched 3-500Zs are about 5 years old, the power supply was rebuilt from kit (Evan may even remember my plaintive cries for help) and I keep a muffin fan over the power supply sucking warm air out. So I promised to do some testing and report back. Here's what I found. First, the setup: Yaesu FT-1000MP Mark V via RG-8X to Drake L-4B L-4B output via RG-213/U to Palstar AT1500DT Output via RG-213/U to Balun Designs 1:1 choke balun (unun) 5 kW model 1115du to Heath Cantenna via RG-8/U patch cable 10+ minute warmup 2600 volts key up in SSB mode 120v AC on a dedicated 15a. circuit Grid current @ 200ma. The results: Band Freqest.drive volts/keydn ma/keydn meter on usual antenna 80 3545.41 40w2250 520 800w 700w 40 7012.54 72w2250 520 800w 900w 20 14063.85 68w2250 520 700w 600w 15 21045.28 70w2250 550 700w 500w 10 28045.11 80w2200 620* 600w 450w Caveats: The Cantenna is by no means the best dummy load but it worked. I have no idea whether the Palstar wattmeter is anywhere near calibrated and it may be frequency-sensitive. Have no idea how accurate the L-4B meters are, but the voltage readings seem to be spot-on, e.g., 1700v in CW/Tune and 2600v in SSB modes. Notes and Observations: 1. Regardless of the accuracy of the Palstar wattmeter, I WAS cranking up the RF power knob on the Yaesu, so I am sure the variation in required input drive is real, though the actual readings are open to question. 2. Also, I only allowed the amp to draw 620 mils on 10 for a few seconds, for test purposes, to keep the drive @ 200 grid mils common. When I backed the drive down to 550 ma on the plate on 10, the grid showed 160 ma. and the wattmeter read 500w. 3. The higher the frequency, the more a minor SWR imbalance showed on the Palstar meter, though never more than 1:1-1. I suspect that this means the Cantenna is not a perfect 50 ohm resistive load; but then, we knew that. 4. The output readings on the dummy load differ sufficiently from what they are with my antennas connected (see above) that it suggests I could do well by doing some work on the transmission lines, coax switch, etc. Nevertheless, something seems to be sub-optimal with the L-4B. It may be time to do some work on the RF deck. The question is, what? Your thoughts and wisdom most welcome, Peter W2CDO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B follow-up
On Sat, 28 Aug 2010 19:17:18 -0400, Ron Baker wrote: from what I can see, from your results the drive power vs. your power output I would say is about what you should expect. I'm with Ron on this one. The L-4B was designed as a 2 KW PEP plate input amp, which translates to about 1200 out (give or take a little). A little less on higher bands. That seems consistent with your numbers, and the other condition that Ron mentions. There's always a little bit of reactance in antennas, no matter how well you try to tune them. In reality, SWR under 2:1 is usable, and under 1.6 isn't worth worrying about. What did hams do before SWR meters? And don't diss the lowly Cantenna. :) It is a proven design that has been a staple of ham shacks for longer than some of us have been hams. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime. HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim.exofire.net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B follow-up
Jim Shorney wrote: On Sat, 28 Aug 2010 19:17:18 -0400, Ron Baker wrote: from what I can see, from your results the drive power vs. your power output I would say is about what you should expect. And don't diss the lowly Cantenna. :) It is a proven design that has been a staple of ham shacks for longer than some of us have been hams. UNLESS the resistor element has been overloaded and/or damaged by certain types of oil coolant and is no longer 50 ohms. The Breune wattmeter circuit becomes very inaccurate in other than a 50 ohm system, not to mention 'other' calibration errors with mismatch problems. Particularly if you plan to measure the RF voltage across the dummy load, it's nice to use the ACTUAL resistance for your calculations! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B and L-7 power supply: Amp plate voltage drops to zero when PTT pressed, help please
Hello, As you may know from my prior post, I have a homebrew 6m 3-500Z amp that I am trying to get to work with a Drake L-7 power supply, so far without success. The amp has an internal power supply, with the HV disconnected. I have the B+ of Drake p/s connected directly to the same spot where the B+ from the internal p/s had been connected, and I have the B- of the the Drake p/s connected to chassis ground. Using a high voltage probe, today I verified that the Drake p/s is providing 2800 vdc directly on the plate of the 3-500Z, when everything is turned on but the PTT is not engaged. But when the PTT is engaged, even with no drive, plate voltage immediately drops to zero. My first thought was a B+ to B- short, but this would have caused a big bang, and nothing is banging or smoking or doing anything unusual at all. No fuse or circuit breaker pops. When the the PTT is pressed, a DPDT relay closes. One side activates the T/R coaxial relay, and the other side grounds the center tap of the filament transformer via the plate current meter. These are the only things that happen when the PTT is engaged. In the absence of a filament to plate short (which would have self-diagnosed with a bang), I can't imagine any reason why pressing the PTT would cause the plate voltage to drop to zero. Anyone have any idea at all what might be going on? It almost seems like the Drake p/s is shutting itself off when the PTT is engaged, and then turning itself back on when the PTT is released. The Drake p/s does not have any sort of internal shut down mechanism, does it? Thanks for any thoughts and 73, Bill NZ5N ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B and L-7 power supply question
Hi, The B- of the power supply for the Drake L-4B and L-7 goes to pin 6 of the Cinch connector. Inside the amp, the B- is floated above ground by a one ohm resistor. The one ohm resistor that floats B- above ground is said to be for the purpose of plate current metering. I do not quite understand how this resistor is needed for plate current meter accuracy. Could someone please tell me how that works? I have an L-7 and a homebrew amp that uses a similar power supply. However, in the homebrew amp the B- goes directly to ground. I'm trying to understand the difference in the configurations. Thanks and 73, Bill NZ5N ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B and L-7 power supply question
Bill - It's just a relatively safer way (low voltage) to measure current of a high voltage supply. Any current that goes OUT of the supply on the positive end MUST come IN via the negative end, or vice-versa depending upon whether you learned your electronics in the military or civilian schools! Anyway, the resistor is near ground, (unless it opens!,) and so connecting it to a panel meter is much safer than having the meter connect across a shunt resistor somewhere up in the HV area of the supply. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Bill Dzurilla wrote: Hi, The B- of the power supply for the Drake L-4B and L-7 goes to pin 6 of the Cinch connector. Inside the amp, the B- is floated above ground by a one ohm resistor. The one ohm resistor that floats B- above ground is said to be for the purpose of plate current metering. I do not quite understand how this resistor is needed for plate current meter accuracy. Could someone please tell me how that works? I have an L-7 and a homebrew amp that uses a similar power supply. However, in the homebrew amp the B- goes directly to ground. I'm trying to understand the difference in the configurations. Thanks and 73, Bill NZ5N ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B and L-7 power supply question
Garey, Thanks for the reply. I still don't get why the resistor is needed. The ammeter is in series with the flow of the current, so what does the resistor do? What would happen if B- went directly to ground? I'm sure the answer is simple but for some reason it is evading me. 73, Bill Bill - It's just a relatively safer way (low voltage) to measure current of a high voltage supply. Any current that goes OUT of the supply on the positive end MUST come IN via the negative end, or vice-versa depending upon whether you learned your electronics in the military or civilian schools! Anyway, the resistor is near ground, (unless it opens!,) and so connecting it to a panel meter is much safer than having the meter connect across a shunt resistor somewhere up in the HV area of the supply. 73, Garey - K4OAH --- On Sat, 5/29/10, Bill Dzurilla billdz@yahoo.com wrote: From: Bill Dzurilla billdz@yahoo.com Subject: L-4B and L-7 power supply question To: drakelist@zerobeat.net Date: Saturday, May 29, 2010, 9:56 AM Hi, The B- of the power supply for the Drake L-4B and L-7 goes to pin 6 of the Cinch connector. Inside the amp, the B- is floated above ground by a one ohm resistor. The one ohm resistor that floats B- above ground is said to be for the purpose of plate current metering. I do not quite understand how this resistor is needed for plate current meter accuracy. Could someone please tell me how that works? I have an L-7 and a homebrew amp that uses a similar power supply. However, in the homebrew amp the B- goes directly to ground. I'm trying to understand the difference in the configurations. Thanks and 73, Bill NZ5N ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B and L-7 power supply question
Bill - This is what happens when I don't look at the manual first! That resistor is there to permit measurement of the GRID current. The center tap of the filament transformer is above ground by that resistor, and the multimeter, in series with calibration pot R16, is connected across R8 to measure GRID current. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Bill Dzurilla wrote: Garey, Thanks for the reply. I still don't get why the resistor is needed. The ammeter is in series with the flow of the current, so what does the resistor do? What would happen if B- went directly to ground? I'm sure the answer is simple but for some reason it is evading me. 73, Bill Bill - It's just a relatively safer way (low voltage) to measure current of a high voltage supply. Any current that goes OUT of the supply on the positive end MUST come IN via the negative end, or vice-versa depending upon whether you learned your electronics in the military or civilian schools! Anyway, the resistor is near ground, (unless it opens!,) and so connecting it to a panel meter is much safer than having the meter connect across a shunt resistor somewhere up in the HV area of the supply. 73, Garey - K4OAH --- On Sat, 5/29/10, Bill Dzurillabilldz@yahoo.com wrote: From: Bill Dzurillabilldz@yahoo.com Subject: L-4B and L-7 power supply question To: drakelist@zerobeat.net Date: Saturday, May 29, 2010, 9:56 AM Hi, The B- of the power supply for the Drake L-4B and L-7 goes to pin 6 of the Cinch connector. Inside the amp, the B- is floated above ground by a one ohm resistor. The one ohm resistor that floats B- above ground is said to be for the purpose of plate current metering. I do not quite understand how this resistor is needed for plate current meter accuracy. Could someone please tell me how that works? I have an L-7 and a homebrew amp that uses a similar power supply. However, in the homebrew amp the B- goes directly to ground. I'm trying to understand the difference in the configurations. Thanks and 73, Bill NZ5N ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B parasitic resistors
On Mon, 2010-03-22 at 19:05 +, AirRadio wrote: I have been working on a pair of my L-4B's and have noticed that the parasitic resistors are a different value on one amp than the other, the first one has 3x 150 Ohms and the second has 3x 15 Ohms, is this a modification or an error, both perform OK just didn't want to run any risks here, these tubes are not getting any cheaper. 73 Max Max, Measure them. 150 can be 150 Ohms or 15 X multiplier of 0 for 15 Ohms, depending on the resistor's manufacturer and Ohmic value coding scheme. Joe, K9HDE ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B parasitic resistors
I have been working on a pair of my L-4B's and have noticed that the parasitic resistors are a different value on one amp than the other, the first one has 3x 150 Ohms and the second has 3x 15 Ohms, is this a modification or an error, both perform OK just didn't want to run any risks here, these tubes are not getting any cheaper. 73 Max -- I am using the free version of SPAMfighter. We are a community of 6 million users fighting spam. SPAMfighter has removed 2596 of my spam emails to date. Get the free SPAMfighter here: http://www.spamfighter.com/len The Professional version does not have this message ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B parasitic resistors
All my L4Bs have three 15 ohm 2 watt resistors. My L7s have two 47 ohm 2 watt resistors. 73, Evan -Original Message- From: AirRadio airra...@dsl.pipex.com To: drakelist@zerobeat.net Sent: Mon, Mar 22, 2010 3:05 pm Subject: [Drakelist] L-4B parasitic resistors I have been working on a pair of my L-4B's and have noticed that the parasitic resistors are a different value on one amp than the other, the first one has 3x 150 Ohms and the second has 3x 15 Ohms, is this a modification or an error, both perform OK just didn't want to run any risks here, these tubes are not getting any cheaper. 73 Max I am using the Free version of SPAMfighter. We are a community of 6 million users fighting spam. SPAMfighter has removed 2596 of my spam emails to date. The Professional version does not have this message. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B parts
Help.. I am in desperate need of both the parasitic chokes that go on top of the two tubes along with the two finned tube tops and also a mint cabinet top for an L-4B, failing that an address of someone that can refinish the cabinet in the original black fleck finish, what is that finish called and does it have a paint code? mine got damaged in an accident :-(( 73 Max -- I am using the free version of SPAMfighter. We are a community of 6 million users fighting spam. SPAMfighter has removed 1456 of my spam emails to date. Get the free SPAMfighter here: http://www.spamfighter.com/len The Professional version does not have this message ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B parts
Thanks for the info, Emailed her right away and the quote is arriving, great list we have here, 73 Max M0GHQ - Original Message - From: k...@aol.com To: airra...@dsl.pipex.com Sent: Tuesday, August 04, 2009 4:27 PM Subject: Re: [Drakelist] L-4B parts Max, Hartzell Mfg. in Miamisburg, OH refinishes Drake cabinets for $45 a piece and $25 shipping, in case you don't get a new top. They are one of the original contractors that did the work for Drake, and they sandblast and powder coat the cabinets. I have three pieces there now. All reports have been very favorable. Crystal Morgan is the contact. 937 859-5955. 73, Mark www.k4so.com www.picasaweb.com/kfourso kfourso.googlepages.com -Original Message- From: AirRadio airra...@dsl.pipex.com To: drakelist@zerobeat.net Sent: Tue, Aug 4, 2009 10:26 am Subject: [Drakelist] L-4B parts Help.. I am in desperate need of both the parasitic chokes that go on top of the two tubes along with the two finned tube tops and also a mint cabinet top for an L-4B, failing that an address of someone that can refinish the cabinet in the original black fleck finish, what is that finish called and does it have a paint code? mine got damaged in an accident :-(( 73 Max -- I am using the Free version of SPAMfighter. We are a community of 6 million users fighting spam. SPAMfighter has removed 1456 of my spam emails to date. The Professional version does not have this message. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.392 / Virus Database: 270.13.43/2280 - Release Date: 08/03/09 17:56:00 -- I am using the free version of SPAMfighter. We are a community of 6 million users fighting spam. SPAMfighter has removed 1456 of my spam emails to date. Get the free SPAMfighter here: http://www.spamfighter.com/len The Professional version does not have this message ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B for sale
Drake L-4B HF AMP for sale This was my dad's rig that he bought new 1969-1970. It is in very good condition, only has some minor scratches below the Load control knob. I have had it stored in my basement since he sold his house to be full time in his RV 10 years ago. This rig is complete without any modifications, and includes the original Instruction Manual, and an extra set of 3-500Z Eimac tubes. Price is $1000.00 plus shipping. I will accept PayPal or cash if picking up. I would prefer local pickup near Minneapolis, MN, or I could arrange to meet you at a reasonable distance for gas expense as this may be expensive to ship. I have pictures upon request, just email me for them. Thanks and 73's Alan, KB0CJP kb0...@gmail.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B POWER SUPPLY
This is everyone's sad moment. I was called to help a widow dispose of her husbands gear but unfortunately I was called after some of the family thought ham gear belonged in the trash. Among other things still left were two L-4B amplifiers both in what appears to be mint condition. So far I was only able to find one power supply. It allowed me to test the amplifiers and they both put out rated power. My questionif I fail to find the second power supply, are there any out there? I can rebuild them. I did order up a capacitor and diode replacement for the one power supply to ensure reliability. I am hoping to bring some money in for the widow. Thanks for reading... Norm W7LFA___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B front panels
Who is the guy that makes repro front panels for Drake gear? I need one for the L-4B. 73 Max M0GHQ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B plate supply upgrade info
Ed, That was a very good article! Ron, do you have that link on your website? Down the road I would like to add an L-4B to my Drake line and I would contemplate incorporating K0GKD's designs into however I power the beast. I have not investigated if some of these issues are addressed with the popular power supply upgrade kit. 73, Eric KA8FAN From: Ed ean...@cinci.rr.com To: drakelist@zerobeat.net Sent: Thursday, January 15, 2009 7:33:28 PM Subject: [Drakelist] L-4B plate supply upgrade info Just wanted to share this article I found on swapping out the power supply,how to handle biasing etc. http://www.k0gkd.com/l4b.html 73, W8KQV-Ed ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B plate supply upgrade
Thanks Eric. I looked high and low for a way to eliminate the 100V bias so any plate supply would work for the L-4B. I'm building a full wave supply with a peter dahl trans for whatever amp I'm powering and this is a great article on what needs to be done. I'll be making the mod soon and will post if I have any trouble whatsoever. I highly recommend the L-4B. Mine has given me many years of service with minimal problems. 73, Ed-W8KQV___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B plate supply upgrade info
Just wanted to share this article I found on swapping out the power supply,how to handle biasing etc. http://www.k0gkd.com/l4b.html 73, W8KQV-Ed___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B plate supply upgrade info
Ed, One thing I notice, is that the builder has the PS stack tight against one another. There's a fair amount of potential difference between all those electrolytic cans, and the sleeving that covers the outer can is NOT typically rated for any serious withstand voltage by most manufacturers. I've had reason to question this in several situations at work and in each case, when I tried to pin the manufacturers as to the breakdown voltage of that PVC sleeving, the answer ultimately was it's there to provide a marking surface, not guaranteed as an insulator). Just my .02 John K5MO At 07:33 PM 01/15/2009, Ed wrote: Just wanted to share this article I found on swapping out the power supply,how to handle biasing etc. http://www.k0gkd.com/l4b.htmlhttp://www.k0gkd.com/l4b.html 73, W8KQV-Ed ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B pwr supply upgrade
Hi Ed, I suggest that you contact Mike Bryce at www.theheathkitshop.com for parts and details on how to rebuild your Drake L-4 power supply. He has an excellent kit of parts and detailed instructions available for this exact purpose at a reasonable price. His address is 955 Manchester Ave. SW, North Lawrence, Ohio 44666. 73, Bob VE3XM - Original Message - From: Ed To: drakelist@zerobeat.net Sent: Friday, January 02, 2009 10:26 PM Subject: [Drakelist] L-4B pwr supply upgrade I am planning on upgrading my L-4PS,increasing the plate voltage by building a complete new supply. I'm not sure what to do about the voltage on cinch plug pin 5 (120V+) ,exactly what it's for or if it is necessary. I haven't found much info but surely someone has done this before. Appreciate any info. Thanks! Ed -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4B pwr supply upgrade
Thanks for the replies! I have already done the upgrade on the original supply. I show about 2700V on SSB and get between 1000-1100 watts at full power. My tubes are mixed,one being an eimac and the other an amperex. I'm not so sure the specs are the same. I have most of the parts for a plate supply other than the transformer anyway so I was considering it. I'm wondering if it would be a big help to swap the tubes with the new graphites. Thanks again and I do love the drakes! Ed-W8KQV___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4B pwr supply upgrade
I am planning on upgrading my L-4PS,increasing the plate voltage by building a complete new supply. I'm not sure what to do about the voltage on cinch plug pin 5 (120V+) ,exactly what it's for or if it is necessary. I haven't found much info but surely someone has done this before. Appreciate any info. Thanks! Ed___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L-4b on 17m warc bands
Before I try this and damage the amp, has anyone used the L-4B on any warc bands with success without altering anything? 73 Max M0GHQ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L-4b on 17m warc bands
I've used my successfully on 12/17m as follows: 17m - Bandswitch in 15m position 12m - Bandswitch in 10m position The Plate and Load controls will depend on your match but my setup puts those two controls in the vicinity: 17m - Plate: bottom end of the 10m arc; Load: about #1 12m - Plate: bottom end of the 10m arc; Load: about #3 YMMV but that should get you in the ballpark. Use a dummy load to find your sweet spots. No warranty specified or implied, you're on you own! Dino KL0S ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[drakelist] L-4B fan
On my L-4B the fan switches off when the power is disconnected (normal), has anyone made a system using the original components to keep the fan running for a few minutes after switch off? I did this with my other linears and it does extend the tube life, trouble is with the L-4B it has a 110v fan that operates through the filament transformer to reduce the 220v to 115v. in order to make it run on you have to have the filaments on which defeats the object a bit and doesn't the psu get hot after a 4 hour contest, I know where I can put my 'Chinese takeaway' next time hihi. ( I have put a fan on that of course), 73 Max
Re: [drakelist] L-4B on AM
Jim Shorney [EMAIL PROTECTED] made an utterance to the drakelist gang -- On Sun, 16 Dec 2007 21:20:51 -, AirRadio wrote: Jim, Thanks for the note, Yes I fully understand the carrier input etc Yes, I thought you might. I Googled you before I responded just to make sure you weren't some CBer looking to walk taller :) I was aiming for roughly 300w carrier maybe that is pushing the L-4b too hard, 300 watts carrier seems to be within the specs. As for how well the L4B handles it, perhaps one of the others can answer; I've never done it, although I did try it briefly with my NCL2000 one time. 73 -Jim -- Jim Shorney --.--Put complaints in this box jshorney (at) inebraska.com Ham Radio NU0C Lincoln, NE, USA EN10ps http://incolor.inetnebr.com/jshorney/ -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] L-4B power supply
Mike D. [EMAIL PROTECTED] made an utterance to the drakelist gang -- I received the e-mail from Milton, TI5MII, shown below. He is rebuilding an L-4B power supply and needs your help. Can someone provide him with the requested pictures? I don't have an L-4B. Thank you. 73 de Mike, N9BOR A-1, FISTS, JARL A-1, SMC http://www.n9bor.us http://www.k9ya.org di dah dit - The only Roger Beep you'll ever need. Let your fingers do the talking - Morse code. My designated driver is a 12BY7A. -Original Message- From: Milton Valerio [mailto:[EMAIL PROTECTED] Sent: Tuesday, March 06, 2007 7:00 PM To: n9bor Subject: L4-PS pictures Hi my name is Milton/TI5MII im dealing with a L-4B, the power supply came to me in a bag totally dissassembled, I assembled it the best I can, replacing electrolytics and resistors following the schematic of the manual. but if someone can provide me some pictures of the interior showing the cables I think can help me to solve some doubdts and also I can be sure it is assembled as it was from the factory. Thanks. Milton -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] L-4B plate current
Garey Barrell [EMAIL PROTECTED] made an utterance to the drakelist gang -- Larry - The idling plate current varies according to the tube type and brand and is determined by the tube construction and Plate voltage applied. With EIMAC 3-500Zs, CW should be 170 mA and SSB should be 260 mA, +/- 10%. 73, Garey - K4OAH Atlanta Drake B C-Line Service CDs http://www.k4oah.com Larry Clark wrote: Larry Clark [EMAIL PROTECTED] made an utterance to the drakelist gang -- What idling plate current should I expect to see on an L-4B in transmit mode, but with no RF drive? I just brought one to life after 20 years on the shelf. After a good cleaning, everything seems fine except I have about 150 mils in the low power CW position and 200 mils in SSB. This seems too high to me, but perhaps not. If this is indeed too much, any suggestions would be appreciated. It tunes up nicely and 3-500's look good, with a nice dull red on the plates when transmitting. The caps all check out fine with the ESR meter, too. TIA 73, Larry, K0RS -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] L-4B plate current
Larry Clark [EMAIL PROTECTED] made an utterance to the drakelist gang -- Many thanks to all who replied to my question. My amp's idling plate current falls squarely between the high and low values suggested, so it looks like I'm good to go. Someone asked a question about shelf life of tubes earlier, and the 3-500 was mentioned. Well, these have seen 20 years of inactivity since being lit according to the gentleman who disposed of this estate equipment. I powered up the filaments for about a half hour before applying RF, and they are performing fine so far. KYFC. The tubes looked new under the grunge. Eimacs, BTW, probably the originals. They are the early style, without the phenolic reinforcing ring on the pins. This may be have been one of the dirtiest pieces of equipment I've ever seen. 20 years of accumulated crud made this project more like an archealogical excavation than a radio restoration. Nice amp underneath it all, though. Also in this cache of equipment (a B line and a C-4 with the antenna relay!) was a 2-B with a dead 25 mHz xtal for the 15 and 10 meter bands. Does anyone have an extra they can spare? Again TIA, Larry, K0RS __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] L-4B plate current
Larry Clark [EMAIL PROTECTED] made an utterance to the drakelist gang -- What idling plate current should I expect to see on an L-4B in transmit mode, but with no RF drive? I just brought one to life after 20 years on the shelf. After a good cleaning, everything seems fine except I have about 150 mils in the low power CW position and 200 mils in SSB. This seems too high to me, but perhaps not. If this is indeed too much, any suggestions would be appreciated. It tunes up nicely and 3-500's look good, with a nice dull red on the plates when transmitting. The caps all check out fine with the ESR meter, too. TIA 73, Larry, K0RS __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
RE: [drakelist] L-4B Capacitor replacement
Ron Baker [EMAIL PROTECTED] made an utterance to the drakelist gang -- All, I have rebuilt about a dozen L4B and L7 power supplies and have had good success and signal reports using standard Mouser parts. For the high voltage rectifier I used the 1N5408 rectifier. This is a 1000V, 3 amp rated rectifier, Mouser price is 12 cents each, what a price. The rectifier is the same size and the original but much heftier that the original. Mouser part number 512-1N5408. For the filter capacitor I use the Xicom 100MF/450V filter capacitor. This is a much smaller axial lead capacitor but they mount in identical to the original and the leads are long enough to reach. The filter is $5.23 each from Mouser, part number 140-XAL450V100. For the circuit purist who say that Drake used 200MF capacitor, I'm sure there are alternatives to those through specialty houses or rebuilding, but from the cost perspective Mouser is your best bet. In the circuit with 200MF capacitors the total capacitance for filtering is 25MF, (8 of the 200MF in series) whereas using the 100MF the total capacitance is 12.5MF. Even with the lower capacitance this is still plenty of filtering for such high voltage. Also, as a side note, if you ever need to replace those two 50 watt load resistors across the top of the power supply, Mouser has exact replacements for those. I just bought a couple and they are a perfect fit and the exact same value. 73, Ron / WB4HFN -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net -- -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] L-4B Power Supply Electrolytics
Steve Berman [EMAIL PROTECTED] made an utterance to the drakelist gang -- Hello To The List: Does anyone have a good source for the 200mfd 450VDC electrolytics used in the L-4B power supply? I'm rebuilding one and would like to find caps as close to the original factory types as possible. Thanks, Steve, N6HK _ Express yourself instantly with MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] L-4B Power Supply Electrolytics
Hi Steve, Odds are that you will not find anything close enough that will fit easily in the space provided. May I suggest that you invest in one of the cap replacement kits offered by The Heathkit Shop. www.theheathkitshop.com You can order the board and get your own components from Mouser or similar parts house or you can order the whole kit from the Heathkit Shop and build it yourself. Mike uses high quality components in his kits and the instructions are easy to read. I have his kits in my L-4B, L-7 and three AC-4 supplies and have had no problems with them. Please noth that I am just a satisfied customer and have no monitary connection with Mike or Mouser. 73, John, W4AWM
[drakelist] L-4B Electrolytic Caps Follow Up
Steve Berman [EMAIL PROTECTED] made an utterance to the drakelist gang -- I want to thank everyone who took the time to answer my post seeking a source for replacement caps. From all the great tips and suggestions, it seems that the best way to go is to order a replacement board from the Heathkit Shop. Also mentioned was Harbach Electronics. Again, thanks and I now have some good ideas on how to proceed with my L-4B power supply rebuild. Steve, N6HK _ FREE pop-up blocking with the new MSN Toolbar get it now! http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/ -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] L-4B Capacitor replacement
Doug [EMAIL PROTECTED] made an utterance to the drakelist gang -- Steve, See this website; http://www89405.temp.w1.com/DRAKE/DrakeArticles/TechTips/ElectrolyticRelacem ents.htm I used this method with a few small modifications solely for beautificatoin purposes. While I was in there I also upgraded the diodes. It worked out very well and was an inexpensive alternative. I believe I ordered the caps from one of the large supply houses, I believe Newark had the cheapest, but I don't remember for sure. You can check pricing at the various suppliers. Good luck and enjoy the amp 73 - Doug N9XTF -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] L-4B Capacitor replacement
Jim Shorney [EMAIL PROTECTED] made an utterance to the drakelist gang -- On Tue, 2 May 2006 22:00:03 -0500, Doug wrote: See this website; http://www89405.temp.w1.com/DRAKE/DrakeArticles/TechTips/ElectrolyticRelacements.htm Nice. I hadn't seen this, thanks Doug. It looks like something I would do. Kudos to Evan and the Marks for this page. -Jim (butt splices should always be soldered) -- TR7/RV7, TR6/RV6, T4XC/R4C, L4B, NCL2000, SB104A, R390A, GT550A/RV550A - all vintage, all the time! -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] L-4B Broken Fan
[EMAIL PROTECTED] made an utterance to the drakelist gang -- My fan was noisy as well, but found that the impeller was loose on its collar. I tried to (super)glue them back together but the plastic is all dried out. May be epoxy will hold better. Any advise where I can get a new impeller? Thanks Nick PA0NCV -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] L-4B fan noise
Tom Taylor \(MSTV\) [EMAIL PROTECTED] made an utterance to the drakelist gang -- Drake Aficionados, I'm putting a recently purchased L-4B back on the air after the amp has experienced an unknown period of inactivity. When I powered up the L-4B last night for the first time, I noticed a rather loud hum coming from the L-4B amp deck. I reached around the back of the unit and stopped the squirrel cage fan with my fingers and the noise stopped. From reading reviews, the L-4B has earned a reputation as being relatively quiet. Has anyone else experienced a loud hum from their L-4B fan? Have you cured it? Can the L-4B's fan motor be lubricated? Curious, Tom N7TM p.s. I made the unobtanium VOX/relay plugs for the amp and ac4 using a suggestion on Garey Barrell's web site. I used 3/16 brass tube for the pins, small rectangles of plexiglass with drilled holes to hold the pins, and epoxy to seal the wires and the back ends of the plugs. -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] L-4B fan noise
Garey Barrell [EMAIL PROTECTED] made an utterance to the drakelist gang -- Tom - The L-4B fan is silent. It has oiler tubes, and Drake recommended oiling with a couple of drops once a year. (Maybe twice?) 73, Garey - K4OAH Atlanta Drake C-Line Service Manual http://www.k4oah.com Tom Taylor (MSTV) wrote: Tom Taylor \(MSTV\) [EMAIL PROTECTED] made an utterance to the drakelist gang -- Drake Aficionados, I'm putting a recently purchased L-4B back on the air after the amp has experienced an unknown period of inactivity. When I powered up the L-4B last night for the first time, I noticed a rather loud hum coming from the L-4B amp deck. I reached around the back of the unit and stopped the squirrel cage fan with my fingers and the noise stopped. From reading reviews, the L-4B has earned a reputation as being relatively quiet. Has anyone else experienced a loud hum from their L-4B fan? Have you cured it? Can the L-4B's fan motor be lubricated? Curious, Tom N7TM p.s. I made the unobtanium VOX/relay plugs for the amp and ac4 using a suggestion on Garey Barrell's web site. I used 3/16 brass tube for the pins, small rectangles of plexiglass with drilled holes to hold the pins, and epoxy to seal the wires and the back ends of the plugs. -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
RE: [drakelist] L-4B fan noise
Tom Taylor \(MSTV\) [EMAIL PROTECTED] made an utterance to the drakelist gang -- Thanks to all who responded with the tip about the L-4B's fan's oil ports. A couple drops of oil in each port immediately solved the noise problem. The L-4B has rejoined the silent ranks. I put it on the air tonight. Man, it heats up my small office quickly. I'm surprised at the tremendous step in plate voltage between the CW and SSB settings. Thanks, Tom N7TM -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Taylor (MSTV) Sent: Tuesday, October 18, 2005 11:11 AM To: drake Subject: [drakelist] L-4B fan noise Tom Taylor \(MSTV\) [EMAIL PROTECTED] made an utterance to the drakelist gang -- Drake Aficionados, I'm putting a recently purchased L-4B back on the air after the amp has experienced an unknown period of inactivity. When I powered up the L-4B last night for the first time, I noticed a rather loud hum coming from the L-4B amp deck. I reached around the back of the unit and stopped the squirrel cage fan with my fingers and the noise stopped. From reading reviews, the L-4B has earned a reputation as being relatively quiet. Has anyone else experienced a loud hum from their L-4B fan? Have you cured it? Can the L-4B's fan motor be lubricated? Curious, Tom N7TM p.s. I made the unobtanium VOX/relay plugs for the amp and ac4 using a suggestion on Garey Barrell's web site. I used 3/16 brass tube for the pins, small rectangles of plexiglass with drilled holes to hold the pins, and epoxy to seal the wires and the back ends of the plugs. -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net -- -- Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] L-4B Power Switch
I am in need of a power switch formy L-4B amp. If you have ajunker or spare switch laying around reply to me direct kf4rrn at cox dotnet. Thanks.Carlos. KF4RRN No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 265.7.1 - Release Date: 1/19/2005
Re: [drakelist] L-4B and TR-7
Lee: Your account is not accepting my mail. Will the L-4B amplifier and the TR-7 Transceiver play together or are modifications required. No modifications are required. Just plug and play. 73, John, W4AWM
Re: [drakelist] L-4B and TR-7
Garey Barrell [EMAIL PROTECTED] made an utterence to the drakelist gang -- Lee - Yes, they work fine. The TR-7 has a real relay in it, similar to the one in the T-4X series, instead of those wimpy little reed jobs the YaeComWoods use.!! Plus the L-4B uses only 30V on the relay, and about 50-60 mA, well within the ratings of the TR-7 relay contacts. 73, Garey - K4OAH Atlanta [EMAIL PROTECTED] wrote: Will the L-4B amplifier and the TR-7 Transceiver play together or are modifications required. Lee NE6C -- On Behalf of Garey Barrell [EMAIL PROTECTED] Submissions:drakelist@www.zerobeat.net Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
[drakelist] L-4B Faceplate
Hi gang! Just acquired an ugly duck. This L-4B is in great operational shape but it looks like crap, to be blunt. Looking for a faceplate to replace this scratched up one. I know there was someone here refinishing them a while back. Also, I am going to repaint the cabinet myself but would be open to a nice set if available. Anyone has any info or source? Thanks, Carlos. KF4RRN
[Drakelist] L-4B Amplifier
Excellent condition, full output, power supply has been completely rebuilt (Caps, Diodes and Resistors). Cabinet shows less than normal wear but is not "mint". The panel is very good with a few very tiny marks from normal use, again not "mint" but very good. The rear chassis has been updated to include an RCA jack for the VOX relay input in addition to the stock Drake two prong plug. Manual included. $750 plus shipping from 46835. Pick up is preferred due the weight of this heavy duty amplifier and power supply. Shipping will be in three boxes (RF Deck, Power Supply and Tubes) and the cost will be the actual cost of packing and shipping via UPS ground. I will also meet a buyer within 100 miles of Fort Wayne, IN. This is one of my personal amps but it is being sold as is due to it's age. It will not be DOA however. Thanks and 73 Mike W9MWS
