[Drakelist] T4XB output meter control
When I press and rotate the output meter control on my T4XB, nothing happens. I have checked the switch and the 68 0hm resistor on it. They are Ok. 73 Peter, OZ8CTH___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] S-meter balance: ain't the tubes - uhh, it was a tube...
Yes, I reset the SENS, as it had increased to -1.45V. I now have much better spread between min and max settings of RG GAIN as well, and can almost get it to 60-over (it hits about 50-over). Steve Wedge, W1ES/4 Live free or die: Death is not the worst of evils. John Stark. All my computers have my signature with various pearls of wisdom appended thereto. -- From: "Garey Barrell" Sent: Saturday, January 14, 2012 9:15 PM To: "Steve Wedge" Cc: "Drake List" Subject: Re: [Drakelist] S-meter balance: ain't the tubes - uhh, it was a tube... Steve - Did you reset RCVR SENS to -1.35 VDC at TP2 AFTER changing V1?? The bridge should balance well within range with about 800 ohms in the two resistive legs. 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 Steve Wedge wrote: It just wasn't one of the tubes in the bridge. Garey's recommendation to change V1 did the trick. My tube tester had passed this, but the minimum transconductance allowable bu the tester chart does NOT get you optimum performance! As an example here, the 6BZ6 has a minimum Gm of 1575 uMhos in the tester rollchart, but a new one is spec'ed with a Gm of 6100 uMhos. Obviously, there's a major difference here, and it's apparent that the RF amp that was in this receiver wasn't performing to new specs. In fact, even before re-doing the S-meter calibration again, I could hear and see (on the meter) the difference in performance. The meter's calibration is still near the edge, but it's no longer at the edge. The receiver is also "hotter" now and the meter is certainly more "lively". I don't know why it hadn't occurred to me that if I had less signal coming in that this could affect the meter's calibration. Thanks for setting my head straight. 73, Steve Wedge, W1ES/4 Live free or die: Death is not the worst of evils. John Stark. All my computers have my signature with various pearls of wisdom appended thereto. -- From: "Garey Barrell" Sent: Thursday, January 12, 2012 9:55 PM To: "Drake List" Subject: Re: [Drakelist] S-meter balance: ain't the tubes. > Couple more possibilities > > Since 'someone' has been 'fixing' the meter, is it still ~ 3mA full > scale & ~ 700 ohms resistance? > > Also, try a new 6BZ6. I have seen cases where a gassy 6BZ6 will drag > down the AGC2 buss, screwing > up the RCVR SENS (R87), which screws up the AGC buss, which ... you get > the picture. Each time you > swap the 6BZ6 recheck for -1.35V at TP2. It may take a couple of > iterations. > > 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 > > > > Steve Wedge wrote: >> R-4B, s/n in the 9000's (I'm too lazy to peek around the back). Had >> previously fried R89 and the >> S-METER ZERO pot and had to replace the pot with a 200-ohm padded with >> a 390-ohm CC. It barely >> reaches S-1 with the pot maxed still. The S-METER SENSITIVITY pot >> which is supposed to be 1k was >> reading 600 ohms, so I padded it with 390 ohms. I can't get the >> needle to reach 60-over with the >> RF GAIN fully CCW. >> I tried replacing V4 an V5 with NOS tubes and there was no change. V2 >> and V3 were likewise >> replaced with no improvement. (V2 was already a new 6HS6 anyway but I >> swapped to be sure). Put >> all the original tubes back in. >> It's a simple bridge, fercryinoutloud! What am I not seeing? > > ___ > 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] T4XB output meter control
Peter, I presume you have power going out (tune or CW). I had a similar problem years back and it turned out to be the switch. A little DeOxit or CaliLube (I forget which) into the contacts and a few exercises of the switch fixed it up for me. 73, Ron WD8SBB --- On Sun, 1/15/12, Peter Ravn wrote: From: Peter Ravn Subject: [Drakelist] T4XB output meter control To: drakelist@zerobeat.net Date: Sunday, January 15, 2012, 10:34 AM When I press and rotate the output meter control on my T4XB, nothing happens. I have checked the switch and the 68 0hm resistor on it. They are Ok. 73 Peter, OZ8CTH -Inline Attachment Follows- ___ 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] T4XB output meter control
Peter, If you have verified continuity through the switch then look at the schematic and you will see there is a 1N270 diode between the output meter control pot and the antenna. If that diode is defective, missing, or has a cold solder joint you will not get any reading. Ken WA2LBI On Sun, Jan 15, 2012 at 10:34, Peter Ravn wrote: > ** > When I press and rotate the output meter control on my T4XB, nothing > happens. I have checked the switch and the 68 0hm resistor on it. They are > Ok. > > 73 Peter, OZ8CTH > ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T4XB output meter control
Peter, Its usually a bad D5 ( 1N270 ) diode. The 68 ohm resistor on the switch is for the plate current function only. 73, Gary http://home.roadrunner.com/~w8pu R-4A T4-X R-4B T4-XB R-4C T4-XC MS-4 L-4B 2A 2B 2C 2NT 2CQ 2AS 4-LF TR-4 TR-4C TR-4CW/RIT RV-4C TR-7 RV-7 CW-75 MS-7 WH-7 W-4 WV-4 MN-2700 MN-4C MN-2000 UV-3 PS-3 PRN1000 TR-22C TR-33C AA-10 AC-10 MMK-22 TR-6___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Ordering CD's and my R-4B
Garey, Please...Check your spam folder for my recent e-mail about ordering CD's and my R-4B S/N 9129R. You don't seem to be getting my e-mails?? Thanks, Lee, KC9CDT -Original Message- From: Garey Barrell To: Steve Wedge Cc: Drake List Sent: Sat, Jan 14, 2012 9:17 pm Subject: Re: [Drakelist] S-meter balance: ain't the tubes - uhh, it was a tube... Steve - Did you reset RCVR SENS to -1.35 VDC at TP2 AFTER changing V1?? The bridge should balance well within range with about 800 ohms in the two resistive legs. 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 Steve Wedge wrote: It just wasn't one of the tubes in the bridge. Garey's recommendation to change V1 did the trick. My tube tester had passed this, but the minimum transconductance allowable bu the tester chart does NOT get you optimum performance! As an example here, the 6BZ6 has a minimum Gm of 1575 uMhos in the tester rollchart, but a new one is spec'ed with a Gm of 6100 uMhos. Obviously, there's a major difference here, and it's apparent that the RF amp that was in this receiver wasn't performing to new specs. In fact, even before re-doing the S-meter calibration again, I could hear and see (on the meter) the difference in performance. The meter's calibration is still near the edge, but it's no longer at the edge. The receiver is also "hotter" now and the meter is certainly more "lively". I don't know why it hadn't occurred to me that if I had less signal coming in that this could affect the meter's calibration. Thanks for setting my head straight. 73, Steve Wedge, W1ES/4 Live free or die: Death is not the worst of evils. John Stark. All my computers have my signature with various pearls of wisdom appended thereto. -- From: "Garey Barrell" Sent: Thursday, January 12, 2012 9:55 PM To: "Drake List" Subject: Re: [Drakelist] S-meter balance: ain't the tubes. > Couple more possibilities > > Since 'someone' has been 'fixing' the meter, is it still ~ 3mA full scale & ~ 700 ohms resistance? > > Also, try a new 6BZ6. I have seen cases where a gassy 6BZ6 will drag down the AGC2 buss, screwing > up the RCVR SENS (R87), which screws up the AGC buss, which ... you get the picture. Each time you > swap the 6BZ6 recheck for -1.35V at TP2. It may take a couple of iterations. > > 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 > > > > Steve Wedge wrote: >> R-4B, s/n in the 9000's (I'm too lazy to peek around the back). Had previously fried R89 and the >> S-METER ZERO pot and had to replace the pot with a 200-ohm padded with a 390-ohm CC. It barely >> reaches S-1 with the pot maxed still. The S-METER SENSITIVITY pot which is supposed to be 1k was >> reading 600 ohms, so I padded it with 390 ohms. I can't get the needle to reach 60-over with the >> RF GAIN fully CCW. >> I tried replacing V4 an V5 with NOS tubes and there was no change. V2 and V3 were likewise >> replaced with no improvement. (V2 was already a new 6HS6 anyway but I swapped to be sure). Put >> all the original tubes back in. >> It's a simple bridge, fercryinoutloud! What am I not seeing? > > ___ > 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
[Drakelist] AC-4 Voltages
Hello All, I'm a newbie to Drake equipment, I just recently purchased a 4-line. When the equipment arrived one of the tubes had come out of the socket in the R-4B and it was broken so I'm waiting for a new tube. Everything looked good in the transmitter but I thought I would look at the voltages from the AC-4 before connecting things up. The voltages seem a bit high to me, but you're the experts. B+ high 769 VDC (checked at orange wire) B+ low313 VDC (checked at yellow wire) BIAS -76 VDC (checked at green wire) 15 VAC filament voltage (checked between black and white wires) All ripple < .004 VAC Too high? v/r Rick Gunderman - WA4RG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
- Original Message - From: "Rick Gunderman" To: Sent: Sunday, January 15, 2012 9:34 AM Subject: [Drakelist] AC-4 Voltages Hello All, I'm a newbie to Drake equipment, I just recently purchased a 4-line. When the equipment arrived one of the tubes had come out of the socket in the R-4B and it was broken so I'm waiting for a new tube. Everything looked good in the transmitter but I thought I would look at the voltages from the AC-4 before connecting things up. The voltages seem a bit high to me, but you're the experts. B+ high 769 VDC (checked at orange wire) B+ low313 VDC (checked at yellow wire) BIAS -76 VDC (checked at green wire) 15 VAC filament voltage (checked between black and white wires) All ripple < .004 VAC Too high? v/r Rick Gunderman - WA4RG Something wrong here. The filament voltage should be 12.5 VAC on a 115VAC power line. The line voltage would have to be nearly 140 volts to produce this filament voltage. All voltages are about 1.2X the correct ones. That makes me suspicious of the meter you are using. What does it measure your line voltage as? I don't think the high voltages are the result of operating without a load although that will raise them somewhat. However, it would not change the bias voltage. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Thank you for your response Richard. Using the same meter, my line voltage reads 122 VAC. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR4 half power
CHECK DIODES IN POWER SUPPLY. THEY ARE NOT HIGH QUALITY TO BEGIN WITH AND THE TUBE REPLACEMENT CAN LOAD ONE OR MORE UP. HAVE SEEN ONE POP ON SEVERAL POWER SUPPLIES AND THIS WILL GIVE YOU ABOUT HALF POWER. DAN k8woz - Original Message - From: Greg Hemmings N4WVE To: drakelist@zerobeat.net Sent: Saturday, January 14, 2012 7:11 PM Subject: [Drakelist] TR4 half power I replaced my 6JB6 tubes and followed the manual instructions for alignment. TX gain is just left of 12:00 at full power and plate amp is just past .3. The bias is set at .1 . Seems like (from what I have heard) it should be more like 180 watts. Any ideas? -- Sent from my Android phone with SkitMail. Please excuse my brevity. -- ___ 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] 2B Fix, Can It be this simple?
Finally found the intermittent static in my R4A by poking around with a plastic tuning tool, revealing the problem was on Board 3, with a (second) bad solder connection, this time at Q8. This was the second bad solder joint on that board, so removed the board and reflowed ALL of the joints. All is good now. So, decided to try the same drill with my 2B which has exhibited a frequency instability of about 200 hz until it has been on for about an hour. While changing out V4 and V3 had no effect, moving V3 a little seemed to cause the warble. Then, I pushed on the T3 can and that seemed focus of the problem. All I did was loosen and then retighten the nuts holding the can to the chassis, and use a tiny amount of deoxit on V3 pins. Now the instability seems to have disappeared. Can it be this simple? Seems strange that this would have solved the problem. 73, Curt KB5JO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Rick - Pretty close for your line voltage. A little high, but not critical. I assume you are measuring just the supply, no load. 750 VDC 300 VDC -70 to -100 VDC 14.5 VAC The filament voltage is high because of the cable and the heavy load (lotsa filaments) 5.5 Amps. 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 Rick Gunderman wrote: Hello All, I'm a newbie to Drake equipment, I just recently purchased a 4-line. When the equipment arrived one of the tubes had come out of the socket in the R-4B and it was broken so I'm waiting for a new tube. Everything looked good in the transmitter but I thought I would look at the voltages from the AC-4 before connecting things up. The voltages seem a bit high to me, but you're the experts. B+ high 769 VDC (checked at orange wire) B+ low313 VDC (checked at yellow wire) BIAS -76 VDC (checked at green wire) 15 VAC filament voltage (checked between black and white wires) All ripple < .004 VAC Too high? v/r Rick Gunderman - WA4RG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Yes sir Garey, no load, just the supply. On Sun, Jan 15, 2012 at 2:17 PM, Garey Barrell wrote: > Rick - > > Pretty close for your line voltage. A little high, but not critical. I > assume you are measuring just the supply, no load. > > 750 VDC > > 300 VDC > > -70 to -100 VDC > > 14.5 VAC > > The filament voltage is high because of the cable and the heavy load > (lotsa filaments) 5.5 Amps. > > 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 > > > > > Rick Gunderman wrote: > >> Hello All, >> >> I'm a newbie to Drake equipment, I just recently purchased a 4-line. >> When the equipment arrived one of the tubes had come out of the socket in >> the R-4B and it was broken so I'm waiting for a new tube. Everything looked >> good in the transmitter but I thought I would look at the voltages from the >> AC-4 before connecting things up. The voltages seem a bit high to me, but >> you're the experts. >> >> B+ high 769 VDC (checked at orange wire) >> B+ low313 VDC (checked at yellow wire) >> BIAS -76 VDC (checked at green wire) >> >> 15 VAC filament voltage (checked between black and white wires) >> >> All ripple < .004 VAC >> >> >> Too high? >> >> >> v/r >> Rick Gunderman - WA4RG >> > ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] 2B Fix, Can It be this simple?
Curt - Not at all! The first step with a 'new' piece of gear, (right after verifying that the CORRECT fuse is in the fuseholder,) is to go through and tighten all hardware, especially that which holds ground lugs or shields to the chassis. You don't see that many bad solder joints on Drake gear, as it was all hand soldered. Unlike Kenwood in the early days of wave soldering!! Ask anyone with a TS-940!! 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 rhule...@comcast.net wrote: Finally found the intermittent static in my R4A by poking around with a plastic tuning tool, revealing the problem was on Board 3, with a (second) bad solder connection, this time at Q8. This was the second bad solder joint on that board, so removed the board and reflowed ALL of the joints. All is good now. So, decided to try the same drill with my 2B which has exhibited a frequency instability of about 200 hz until it has been on for about an hour. While changing out V4 and V3 had no effect, moving V3 a little seemed to cause the warble. Then, I pushed on the T3 can and that seemed focus of the problem. All I did was loosen and then retighten the nuts holding the can to the chassis, and use a tiny amount of deoxit on V3 pins. Now the instability seems to have disappeared. Can it be this simple? Seems strange that this would have solved the problem. 73, Curt KB5JO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
- Original Message - From: "Rick Gunderman" To: "Richard Knoppow" <1oldle...@ix.netcom.com> Cc: Sent: Sunday, January 15, 2012 9:56 AM Subject: Re: [Drakelist] AC-4 Voltages Thank you for your response Richard. Using the same meter, my line voltage reads 122 VAC. A puzzle. I have two AC-4's both with the Heathkit shop mods in them. By memory I did not get extra-high voltages on either. One is where I can get to it and will see if I can make some measurements with it unloaded. 122 VAC is typical of current power company practice and is not high enough to account for the differences between specified and measured voltages. I measured the voltages of one of my AC-4's. Measurements with a Triplet 630, 20k ohms per volt DC. I double checked some of the voltages with a Tektronix DMM245 which read essentially the same. Line voltage = 114 VAC HV = +650 VDC Medium HV = +270 VDC Bias, adjustable from about -45 VDC to about -70 VDC Filament, about 13 VAC All measured to chassis ground. All are unloaded voltages, i.e., the supply was not connected to a transmitter. This is pretty close to the values on the schematic. A label on the back of this unit states that it was rebuilt by Jeff Cavelli. My other one is burried a bit but by memory the voltages were nearly the same as this one. I can think of a lot of reasons for the voltages to be _low_ but not many for it to be high, especially by this much. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
When I did an AC-4R board kit replacement with a relatively high serial number (>55,000) unit, in the final checkout I got these DC voltages (NO LOAD): 717 (orange) 292 (yellow) -64 (green). This value of course is variable. Did not measure filament voltage, but I have some non-loaded numbers from six unrestored units (two being AC-3's) ranging from 12.6 to 13.3 vac. (119.8 vac power). 73, Mark N5KAE - Original Message > From: Richard Knoppow <1oldle...@ix.netcom.com> > To: Rick Gunderman > Cc: drakelist@zerobeat.net > Sent: Sun, January 15, 2012 1:43:20 PM > Subject: Re: [Drakelist] AC-4 Voltages > > > - Original Message - From: "Rick Gunderman" > To: "Richard Knoppow" <1oldle...@ix.netcom.com> > Cc: > Sent: Sunday, January 15, 2012 9:56 AM > Subject: Re: [Drakelist] AC-4 Voltages > > > > Thank you for your response Richard. Using the same meter, my line voltage > > reads 122 VAC. > > > > A puzzle. I have two AC-4's both with the Heathkit shop mods in them. By >memory I did not get extra-high voltages on either. One is where I can get to >it >and will see if I can make some measurements with it unloaded. > 122 VAC is typical of current power company practice and is not high > enough >to account for the differences between specified and measured voltages. > I measured the voltages of one of my AC-4's. Measurements with a Triplet >630, 20k ohms per volt DC. I double checked some of the voltages with a >Tektronix DMM245 which read essentially the same. > > Line voltage = 114 VAC > HV = +650 VDC > Medium HV = +270 VDC > Bias, adjustable from about -45 VDC to about -70 VDC > Filament, about 13 VAC > All measured to chassis ground. > All are unloaded voltages, i.e., the supply was not connected to a transmitter. > > This is pretty close to the values on the schematic. A label on the back of >this unit states that it was rebuilt by Jeff Cavelli. My other one is burried >a >bit but by memory the voltages were nearly the same as this one. > I can think of a lot of reasons for the voltages to be _low_ but not many >for it to be high, especially by this much. > > > -- > Richard Knoppow > Los Angeles > WB6KBL > dickb...@ix.netcom.com > > > ___ > 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] AC-4 Voltages
Hey, Rick - Welcome to the World-O-Drake. Those voltages sound about right for an unloaded supply. They do drop once you connect a transmitter to the supply. 73, Steve Wedge, W1ES/4 Live free or die: Death is not the worst of evils. John Stark. All my computers have my signature with various pearls of wisdom appended thereto. From: Rick Gunderman Sent: Sunday, January 15, 2012 12:34 PM To: drakelist@zerobeat.net Subject: [Drakelist] AC-4 Voltages Hello All, I'm a newbie to Drake equipment, I just recently purchased a 4-line. When the equipment arrived one of the tubes had come out of the socket in the R-4B and it was broken so I'm waiting for a new tube. Everything looked good in the transmitter but I thought I would look at the voltages from the AC-4 before connecting things up. The voltages seem a bit high to me, but you're the experts. B+ high 769 VDC (checked at orange wire) B+ low313 VDC (checked at yellow wire) BIAS -76 VDC (checked at green wire) 15 VAC filament voltage (checked between black and white wires) All ripple < .004 VAC Too high? v/r Rick Gunderman - WA4RG ___ 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] AC-4 Voltages
Thank you all for your replies. This week after I receive my 6EH5 in and get the receiver going I'll turn the transmitter on and see what happens. ' 73 Rick - WA4RG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] 2B Fix, Can It be this simple?
Curt, with stuff this old, it's not a surprise. I use Cramolin on my tube pins and it helps a lot. An old war story: I bought a nice-looking NC-300 for $15 (!) at a hamfest in the 90's (that was a steal even back then!). The seller said it was intermittent. Some Cramolin on the tube pins solved the problem - I used the RX for a number of years before selling it at market price. Sometimes it really is THAT simple :) Steve Wedge, W1ES/4 Live free or die: Death is not the worst of evils. John Stark. All my computers have my signature with various pearls of wisdom appended thereto. -- From: Sent: Sunday, January 15, 2012 1:53 PM To: Subject: [Drakelist] 2B Fix, Can It be this simple? Finally found the intermittent static in my R4A by poking around with a plastic tuning tool, revealing the problem was on Board 3, with a (second) bad solder connection, this time at Q8. This was the second bad solder joint on that board, so removed the board and reflowed ALL of the joints. All is good now. So, decided to try the same drill with my 2B which has exhibited a frequency instability of about 200 hz until it has been on for about an hour. While changing out V4 and V3 had no effect, moving V3 a little seemed to cause the warble. Then, I pushed on the T3 can and that seemed focus of the problem. All I did was loosen and then retighten the nuts holding the can to the chassis, and use a tiny amount of deoxit on V3 pins. Now the instability seems to have disappeared. Can it be this simple? Seems strange that this would have solved the problem. 73, Curt KB5JO ___ 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] AC-4 Voltages
Old AC-4 ... no AC-4R rebuild, original parts no load ... 718 vdc 286 vdc -70 vdc 13.8 vac ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
Mark - Interesting. A primary voltage of 121.5 VAC resulted in measured AC voltages out of the transformer at 266 VAC, 108 and 98. The filament measured 14 VAC, all no load. 266 x 2.828 = 752 V peak 108 x 2.828 = 305 V peak Both have very high bleeders, a mA or two so will reach near these peak voltages at no load. 98 x 28.28 = 138 V peak. The divider on the output is nominally 69 VDC at mid-range with NO load. The transmitter is specified as a 33k ohm load. All measurements taken with a calibrated Fluke DMM. 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 Mark Nace wrote: When I did an AC-4R board kit replacement with a relatively high serial number (>55,000) unit, in the final checkout I got these DC voltages (NO LOAD): 717 (orange) 292 (yellow) -64 (green). This value of course is variable. Did not measure filament voltage, but I have some non-loaded numbers from six unrestored units (two being AC-3's) ranging from 12.6 to 13.3 vac. (119.8 vac power). 73, Mark N5KAE - Original Message From: Richard Knoppow<1oldle...@ix.netcom.com> To: Rick Gunderman Cc: drakelist@zerobeat.net Sent: Sun, January 15, 2012 1:43:20 PM Subject: Re: [Drakelist] AC-4 Voltages - Original Message - From: "Rick Gunderman" To: "Richard Knoppow"<1oldle...@ix.netcom.com> Cc: Sent: Sunday, January 15, 2012 9:56 AM Subject: Re: [Drakelist] AC-4 Voltages Thank you for your response Richard. Using the same meter, my line voltage reads 122 VAC. A puzzle. I have two AC-4's both with the Heathkit shop mods in them. By memory I did not get extra-high voltages on either. One is where I can get to it and will see if I can make some measurements with it unloaded. 122 VAC is typical of current power company practice and is not high enough to account for the differences between specified and measured voltages. I measured the voltages of one of my AC-4's. Measurements with a Triplet 630, 20k ohms per volt DC. I double checked some of the voltages with a Tektronix DMM245 which read essentially the same. Line voltage = 114 VAC HV = +650 VDC Medium HV = +270 VDC Bias, adjustable from about -45 VDC to about -70 VDC Filament, about 13 VAC All measured to chassis ground. All are unloaded voltages, i.e., the supply was not connected to a transmitter. This is pretty close to the values on the schematic. A label on the back of this unit states that it was rebuilt by Jeff Cavelli. My other one is burried a bit but by memory the voltages were nearly the same as this one. I can think of a lot of reasons for the voltages to be _low_ but not many for it to be high, especially by this much. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Interesting discovery/problem about R-4A & R-4B
OK,...all Regarding this issue... I have done a lot of work on it and: I see the wiring is different for: The R-4A S/N 5900 R-4B S/N 9129 (That fails the same way as the R-4A) R-4B S/N 10851 That I have here currently. All 3 are different! I can not run the R-4B S/N 10,851 right now as I have the PTO out...clearing the UV imposed browning on the dial. Using Reto-Bright. So I don't know if it fails, but I think it will not... So, I have a Schematic for $-4A, and R-4B S/N 10851. I need a schematic for -4B S/N 9129 so I can see what to change to make it like the newer one. Please, can someone provide the Schematic for the R-4B S/N 9129 vintage?? I only need the part that covers the V3, V9, V10, V4, area. Thanks, 73, Lee -Original Message- From: Garey Barrell To: kc9cdt Cc: drakelist Sent: Fri, Jan 13, 2012 9:44 am Subject: Re: [Drakelist] Interesting discovery/problem about R-4A & R-4B Lee - What is the serial number of your R-4B??? 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 kc9...@aol.com wrote: Gary, Thanks for the information...yes,,,I get the clicking/static like sound as described. Not distortion...that is of course normal when the opposite SB is heard. D3 is fine...Good F/B ratio If you are tuned into a strong signal kind of by itself, of course you won't be hearing the wrong SB at all...BUT, If there is a adjacent strong signal and his 'wrong SB' is in the front end PB...you hear the clicking and it is pretty bad. It is the worst (of course) when you listen to a weak or moderate signal and a strong signal is nearby. The R-4A AND the R-4B here do exactly the same thing. My R-4C does not. I do not hink it is something only wrong with THIS R-4A. It would be nice if others with a R-4A or B would see if they hear it to... From a tech. standpoint my last post here describes exactly what is happening. Be nice to find a solution so anyone wanting it could install it. 73, Lee -Original Message- From: Gary Winblad To: kc9cdt Cc: drakelist Sent: Thu, Jan 12, 2012 10:53 pm Subject: Re: [Drakelist] Interesting discovery/problem about R-4A & R-4B I think what you are describing is perfectly normal. Strong signals within the "roofing" 10Kc(KHz) filter WILL upset your desired weaker signal. The NB works by detecting and killing sharp noise spikes BEFORE they get lengthened by passing through the narrow IF filter. IIRC, it was a Drake innovation to limit the NB detection bandwidth to 10Kc. AVC is generated after the sharp IF filter, and the stronger the signal, the more the AVC cuts gain starting with V1, just as you have described. The only problem seems to be that you say you get the strong signal distortion even with the NB turned OFF, that is not right... IMHO. Like Garey already suggested, problems near D3 and the NB switch is most likely I would think, this is where the NB gets turned OFF, V9 should be running the same with NB on or off. 73, Gary WB6OGD - Original Message - From: kc9...@aol.com To: drakelist@zerobeat.net Sent: Thu, 12 Jan 2012 20:18:38 - (UTC) Subject: [Drakelist] Interesting discovery/problem about R-4A & R-4B Drake Enthusiasts, While working on a Drake R-4A..(11 tube) .I discovered something that bothered me...and thought for sure it was a problem needing fixing! Yeah...I do like things to work well. OK...find a nice STRONG signal...maybe S-9 ++ (20 over) tune it in it sounds great...OK...now carefully tune to the opposite sideband of that same signal. NB is off...not that it matters, now...listen carefully...of course you hear the garbled opposite sideband...BUT also you hear a lot of clicking/arcing like noise on voice peaks especially. Loud enough to be a botherIF you PULL the Noise blanker tube V9 and or V10...the noise goes away! Huh! the NB is OFF, so why do we hear that racket?And why does pulling the tube fix it? Well go off looking to see what's wrong so I can fix itspent quite a lot of timelooked at lots of things with the scope. Discovered what was going on is: If you scope the grid or plate of V9 the 50 kc NB amp...you see a relatively small signal when the signal is tuned into the correct SB...BUT if you look at it when tuned to the wrong SB...WOW huge signal level (maybe 5-10 times as strong) ...and that signal level is getting through the NB amp, shaper and amp...and clamping the plate of V4 the IF amp right before the PB tuning...thus creating the annoying clicking sounds. That's why it stops when you pull the NB tube(s). So, got to looking at the AVC signals and how it works at the grid of V9 the 50 kc amp going into the NB sectionfound out the AVC does not throttle back as much with a wrong SB sigal as the properly tunes one! So the signal. Why is this a problem since we don't really listen to the wrong SB? Well, IF you are listening to a nice signal AND
[Drakelist] FS - T-4X
I've got a decently-performing, but somewhat dusty, T-4X that I'm going to offer to the Drakelist before I consider refurbing it - in case anyone on the Drakelist needs a working transmitter. The transmitter works fine on 80 - 10: I bought it with my R-4B that I'm currently using and now that I've got a T-4XB to go with it, it's an extra transmitter. No real problems, no holes, decent cosmetically. Please email me if interested. Steve Wedge, W1ES/4 Live free or die: Death is not the worst of evils. John Stark. All my computers have my signature with various pearls of wisdom appended thereto. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AC-4 Voltages
- Original Message - From: "Garey Barrell" To: Sent: Sunday, January 15, 2012 1:27 PM Subject: Re: [Drakelist] AC-4 Voltages Mark - Interesting. A primary voltage of 121.5 VAC resulted in measured AC voltages out of the transformer at 266 VAC, 108 and 98. The filament measured 14 VAC, all no load. 266 x 2.828 = 752 V peak 108 x 2.828 = 305 V peak Both have very high bleeders, a mA or two so will reach near these peak voltages at no load. 98 x 28.28 = 138 V peak. The divider on the output is nominally 69 VDC at mid-range with NO load. The transmitter is specified as a 33k ohm load. All measurements taken with a calibrated Fluke DMM. 73, Garey - K4OAH Glen Allen, VA I remeasured both supplies. Unloaded and with line voltage at about 120VAC, I get HV= +702 VDC on both. Only measured medium voltage on one and filament on one. MV= +287VDC Filament= 13.8 VAC Didn't remeasure the bias. Meter: Tektronix DMM 254 These were all measured at the end of the power plug with a jumper across the line switch contacts. I actually opened up a supply to measure the first voltages. Not sure where the difference came from. FWIW, wire doesn't work well to short the plug, I used bits of cut-off paper clip and that worked fine. It appears that the original poster's voltages are fine although I still think the filament is high. Since that is a matter of the turns ratio of the transformer it may still be a measurement error. The voltages that count are those measured with the transmitter working. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
