[Drakelist] TR7 No Standby or Mute
Hi guys, This morning during my vintage AM net, my antenna changeover relay decided to quit on me, so I switched on my TR7 to use as a receiver. As there's no standby mode, before transmitting (100 watts) I turned the RF and AF gain all the way down and manually switched the antenna to the TR7 with the coax switch. It didn't work so well though. As I often have both rigs on at a time, it would be nice to be able to mute the ones not in use rather than turn them off, especially those that need to stay warm. I've looked through the TR7 manual, but I can't seem to find anything on a standby mode. Does anybody know of a way to use the TR7's receiver with another transmitter? Thanks 73, Tony K4KYO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 No Standby or Mute
Tony - I'm not aware of any external 'Standby' control for the TR-7 receiver. A quick look at the schematic shows that the AF OUTPUT chip has it's own +13.6 VDC source on Pin 30 of the 2nd IF/AF board. There is a 22 uF cap on the line, so the cut off 'might' be a little slow, but it looks like you could just interrupt that supply and MUTE the receiver. There may be another way to inhibit a part of the 10R bus, (the 'normal' standby internally is accomplished by turning off the entire 10R bus,) so that could also be done by control on the Transmit/Exciter board via Q307 and Q308. Grounding the Base of Q308 would MUTE the receiver. Unfortunately that is the inverse of Drake MUTE circuits which OPEN a ground connection to MUTE the receiver, so an inverter stage would be necessary. Still only a transistor/resistor to invert. There are a few spare pins and at least one RCA jack on the back panel that could be used. 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 Richard A. (Tony) Stalls wrote: Hi guys, This morning during my vintage AM net, my antenna changeover relay decided to quit on me, so I switched on my TR7 to use as a receiver. As there's no standby mode, before transmitting (100 watts) I turned the RF and AF gain all the way down and manually switched the antenna to the TR7 with the coax switch. It didn't work so well though. As I often have both rigs on at a time, it would be nice to be able to mute the ones not in use rather than turn them off, especially those that need to stay warm. I've looked through the TR7 manual, but I can't seem to find anything on a standby mode. Does anybody know of a way to use the TR7's receiver with another transmitter? Thanks 73, Tony K4KYO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 No Standby or Mute
Hi Garey, My first reaction is, Wow! I was hoping there was already a muting circuit, as with the TR7-R7 pairing, but in that case I doubt anyone would use the TR7 as the receiver. I'll get my Service Manual out and go from there. Thanks much! VY 73, Tony K4KYO At 01:28 PM 2/23/2011, Garey Barrell wrote: Tony - I'm not aware of any external 'Standby' control for the TR-7 receiver. A quick look at the schematic shows that the AF OUTPUT chip has it's own +13.6 VDC source on Pin 30 of the 2nd IF/AF board. There is a 22 uF cap on the line, so the cut off 'might' be a little slow, but it looks like you could just interrupt that supply and MUTE the receiver. There may be another way to inhibit a part of the 10R bus, (the 'normal' standby internally is accomplished by turning off the entire 10R bus,) so that could also be done by control on the Transmit/Exciter board via Q307 and Q308. Grounding the Base of Q308 would MUTE the receiver. Unfortunately that is the inverse of Drake MUTE circuits which OPEN a ground connection to MUTE the receiver, so an inverter stage would be necessary. Still only a transistor/resistor to invert. There are a few spare pins and at least one RCA jack on the back panel that could be used. 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 Richard A. (Tony) Stalls wrote: Hi guys, This morning during my vintage AM net, my antenna changeover relay decided to quit on me, so I switched on my TR7 to use as a receiver. As there's no standby mode, before transmitting (100 watts) I turned the RF and AF gain all the way down and manually switched the antenna to the TR7 with the coax switch. It didn't work so well though. As I often have both rigs on at a time, it would be nice to be able to mute the ones not in use rather than turn them off, especially those that need to stay warm. I've looked through the TR7 manual, but I can't seem to find anything on a standby mode. Does anybody know of a way to use the TR7's receiver with another transmitter? Thanks 73, Tony K4KYO ___ 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] Drakelist Digest, Crystal calabrator Gone south?
Crystal calibrator on the Drake B line twins. Is this an easy fix or expensive fix or is it something I could locate and fix myself? What equipment is required to locate and repair this item. Looking at he schematic it could be a transistor or and IC in the receiver. Any thoughts? 73 de Fred WD8ADG ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drakelist Digest, Crystal calabrator Gone south?
Fred, Before you try to fix the calibrator, make sure it truly is not working and it isn't just a matter of your not having a shorting plug in the MUTE jack. If you don't put a shorted RCA plug in that jack the CAL won't work. 73/Paul, K4MSG In a message dated 2/23/2011 6:03:43 P.M. Eastern Standard Time, fjmel...@aol.com writes: Crystal calibrator on the Drake B line twins. Is this an easy fix or expensive fix or is it something I could locate and fix myself? What equipment is required to locate and repair this item. Looking at he schematic it could be a transistor or and IC in the receiver. Any thoughts? 73 de Fred WD8ADG ___ 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] Drakelist Digest, Crystal calabrator Gone south?
Fred - Most likely it's a power supply problem. If you have a DMM or VOM it would be easy to check. There's a diode and a couple of electrolytic caps that ONLY power the Calibrator's Buffer and Divider stages. D16, R158, R157, C190 and C192. It's a half-wave rectifier from the filament supply. If you have a meter, check the DC voltage at the (+) end of C192 which is a silver colored tubular electrolytic right by the AC line input _WATCH FOR HIGH VOLTAGE_ .. You should measure about 15 VDC or so there. If there is much lower or no voltage there, then it will need replacing. It's possible that failing also damaged D16 and/or R158. If you have voltage there, then check on the (+) end of C190, which is on the Calibrator board, UNDER the crystal. It's a black tubular electrolytic. and you should see about 4 VDC there. 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 fjmel...@aol.com wrote: /Crystal calibrator on the Drake B line twins. Is this an easy fix or expensive fix or is it something I could locate and fix myself? What equipment is required to locate and repair this item. Looking at he schematic it could be a transistor or and IC in the receiver. Any thoughts? / // /73 de Fred WD8ADG/ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drakelist Digest, Crystal calabrator Gone south?
Paul - Good idea!! If the receiver goes 'dead' in the CALIBRATE position, find that shorting plug! (Or connect the cable to the MUTE on receiver and transmitter.) 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 ph...@aol.com wrote: Fred, Before you try to fix the calibrator, make sure it truly is not working and it isn't just a matter of your not having a shorting plug in the MUTE jack. If you don't put a shorted RCA plug in that jack the CAL won't work. 73/Paul, K4MSG In a message dated 2/23/2011 6:03:43 P.M. Eastern Standard Time, fjmel...@aol.com writes: /Crystal calibrator on the Drake B line twins. Is this an easy fix or expensive fix or is it something I could locate and fix myself? What equipment is required to locate and repair this item. Looking at he schematic it could be a transistor or and IC in the receiver. Any thoughts? / // /73 de Fred WD8ADG/ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] L4B power supply fire!
Just as I have heard all the stories of power supplies being destroyed, my L4B power supply did just that. Turned on the amplifier just like I always have heard a big bang and looking to find the noise and then saw the fire. Turned off the L4B and removed the 220 volt plug from the wall just in time to see my power supply burning. I then carried it outside until the fire was out. I had planned to upgrade the power supply but now it's got to happen. I would like to ask about the Heath Kit shop, power supply module upgrade. Has anybody used this unit? When this unit is purchased does this unit replace both sets of 220uf 450 volt old yellow caps and all the resistors and diodes? Any comments, ideas, or suggestions would be appreciated! Thank you Michael J Trussell KA8ASN ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Looking For Filter
Hi All, OK, I'm going fishing here. Does anyone on list have a 6 kHz AM filter for the R4C you would consider selling? If so, I'd like to visit with you about it. Thanks much and very 73. Kevin :) Amateur Radio: K7RX ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] L4B power supply fire!
Michael, I have rebuilt several supplies and have used both the Harbach Electronics board and the HeathkitShop board; only difference is that the latter has space for equalizing resistors for the diodes whereas the former you have to add them directly to the diodes themselves should you choose to add them. Make sure you replace the 5K 7wt resistor on the bottom of the cabinet with a higher wattage; I use two 10K 10 watt resistors in parallel to get the functional equivalent but a higher wattage. Make sure you replace the two 50 K 50 wt resistors as well. As a final touch, I add a 220 v fan to the top, ones that are known to start and run reliably on 110 vac, can't hear them run, and the installation is not permanent. Good luck with your project. 73, Evan -Original Message- From: Michael Sue Trussell mtruss8...@comcast.net To: drakelist@zerobeat.net Sent: Wed, Feb 23, 2011 8:23 pm Subject: [Drakelist] L4B power supply fire! Just as I have heard all the stories of power supplies being destroyed, my L4B power supply did just that. Turned on the amplifier just like I always have heard a big bang and looking to find the noise and then saw the fire. Turned off the L4B and removed the 220 volt plug from the wall just in time to see my power supply burning. I then carried it outside until the fire was out. I had planned to upgrade the power supply but now it’s got to happen. I would like to ask about the Heath Kit shop, power supply module upgrade. Has anybody used this unit? When this unit is purchased does this unit replace both sets of 220uf 450 volt old yellow caps and all the resistors and diodes? Any comments, ideas, or suggestions would be appreciated! Thank you Michael J Trussell KA8ASN ___ 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] R-4C roofing filter
Can someone explain the Sherwood roofing filter mods? Can you select the bandwidth of the filter? Is the CF-2K/8 the only filter available? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
