[Drakelist] FS;Manual
Drake T-4X, T-4, bound copy= $7.50 plus shipping. If you are interested, please e-mail me direct TNXDoug W7LNB dd...@centurytel.net ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 VFO Problem ?
On Fri, 18 Dec 2009 10:06:44 -0500, Garey Barrell wrote: >Jim's suggestion to check the 24 VDC supply is a good one. A common >cause of failure is the top "half" of the DC-DC converter transformer >core falls off, or just becomes separated enough to cause the voltage to >drop. Looking at the "top" of the transformer on the Power Supply board >(one with the pots), you should see a solid bar. If you see three >"ends" of an "E" sticking up, look for the top half of the "E" shaped >core in the bottom of the case. If gone, replacements can be had from >Charlie, K3ICH. Thanks, Garey! :) I would add to that, as long as the OP has the board out and is working on it, replace any electrolytic capacitors with new 105C teperature rated caps. These caps are getting old, and can cause some interesting operational anomalies when they start to go bad. 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(dot)exofire(dot)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] TR7 VFO Problem ?
Joe - VERY good point!! I sometimes don't go far enough 'back'! :-) ALL buttons on the front panel should be OUT to start! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs Joe Pyles wrote: Also make sure the Fixed buttons on the front of the radio are not depressed, and check that the PTO is indeed putting out a signal as the synthesizer won't lock without PTO input. 73 Joe KC9LAD At 10:06 AM 12/18/2009, you wrote: Adrian - Changing the pots to multiturn will have NO effect upon the synthesizer operation. Again, it doesn't hurt, but isn't _necessary_ for proper operation. You definitely have a synthesizer problem, either in the VCOs or the reference frequencies. Verify that you have the 500 kHz reference, and then check for the 500 kHz input from the divider chain. Jim's suggestion to check the 24 VDC supply is a good one. A common cause of failure is the top "half" of the DC-DC converter transformer core falls off, or just becomes separated enough to cause the voltage to drop. Looking at the "top" of the transformer on the Power Supply board (one with the pots), you should see a solid bar. If you see three "ends" of an "E" sticking up, look for the top half of the "E" shaped core in the bottom of the case. If gone, replacements can be had from Charlie, K3ICH. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs http://www.k4oah.com/> > Adrian Rees (MW1LCR) wrote: Hello all I have the Service Manual and have it printed out. To confirm the symptoms, on 21 and 28MHz the counter settles around 33.030MHz and 17.206MHz on all other bands. Connecting an antenna I can "hear" my signal generator on thes frequencies (sweeping the generator through the 33 and 17MHz frequencies). With an external source the counter works fine. So the synthesizer doesn't appear to be locking. I have cleaned the Molex connectors. My next course of action is to replace the pots on the voltage control board for multiturn ones, and re-align the voltages etc, and then re-check the synthesizer board again. Thanks all for the help, so far ! Adrian MW1LCR ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 VFO Problem ?
Also make sure the Fixed buttons on the front of the radio are not depressed, and check that the PTO is indeed putting out a signal as the synthesizer won't lock without PTO input. 73 Joe KC9LAD At 10:06 AM 12/18/2009, you wrote: Adrian - Changing the pots to multiturn will have NO effect upon the synthesizer operation. Again, it doesn't hurt, but isn't _necessary_ for proper operation. You definitely have a synthesizer problem, either in the VCOs or the reference frequencies. Verify that you have the 500 kHz reference, and then check for the 500 kHz input from the divider chain. Jim's suggestion to check the 24 VDC supply is a good one. A common cause of failure is the top "half" of the DC-DC converter transformer core falls off, or just becomes separated enough to cause the voltage to drop. Looking at the "top" of the transformer on the Power Supply board (one with the pots), you should see a solid bar. If you see three "ends" of an "E" sticking up, look for the top half of the "E" shaped core in the bottom of the case. If gone, replacements can be had from Charlie, K3ICH. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs Adrian Rees (MW1LCR) wrote: Hello all I have the Service Manual and have it printed out. To confirm the symptoms, on 21 and 28MHz the counter settles around 33.030MHz and 17.206MHz on all other bands. Connecting an antenna I can "hear" my signal generator on thes frequencies (sweeping the generator through the 33 and 17MHz frequencies). With an external source the counter works fine. So the synthesizer doesn't appear to be locking. I have cleaned the Molex connectors. My next course of action is to replace the pots on the voltage control board for multiturn ones, and re-align the voltages etc, and then re-check the synthesizer board again. Thanks all for the help, so far ! Adrian MW1LCR ___ 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] TR7 VFO Problem ?
Adrian - Changing the pots to multiturn will have NO effect upon the synthesizer operation. Again, it doesn't hurt, but isn't _necessary_ for proper operation. You definitely have a synthesizer problem, either in the VCOs or the reference frequencies. Verify that you have the 500 kHz reference, and then check for the 500 kHz input from the divider chain. Jim's suggestion to check the 24 VDC supply is a good one. A common cause of failure is the top "half" of the DC-DC converter transformer core falls off, or just becomes separated enough to cause the voltage to drop. Looking at the "top" of the transformer on the Power Supply board (one with the pots), you should see a solid bar. If you see three "ends" of an "E" sticking up, look for the top half of the "E" shaped core in the bottom of the case. If gone, replacements can be had from Charlie, K3ICH. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs Adrian Rees (MW1LCR) wrote: Hello all I have the Service Manual and have it printed out. To confirm the symptoms, on 21 and 28MHz the counter settles around 33.030MHz and 17.206MHz on all other bands. Connecting an antenna I can "hear" my signal generator on thes frequencies (sweeping the generator through the 33 and 17MHz frequencies). With an external source the counter works fine. So the synthesizer doesn't appear to be locking. I have cleaned the Molex connectors. My next course of action is to replace the pots on the voltage control board for multiturn ones, and re-align the voltages etc, and then re-check the synthesizer board again. Thanks all for the help, so far ! Adrian MW1LCR ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 VFO Problem ?
Adrian, Be aware of what is mentioned before by Garey - K4OAH. When changing the pots, the 10V-DC will not be the same voltage as before. Changing that voltage requires a full alignment of the TR7. So, before you start removings the pots, warm up the TR7 for a minute or 10. Than measure the 10V-DC with a digital voltmeter as accurate as possible and write down the value on a piece of paper. After that you can replace the pots and ,after warming up the TR7 again, adjust the 10V-DC voltage to exactly the same value as measured before. After that you can re-align the other pots as described in the manual. This is not a guarantee that the TR7 needs a complete aligment yet, but I think it's the best way to replace the pots. Good luck, Carel - PA0CMU. > From: ree...@btconnect.com > To: drakelist@zerobeat.net > Date: Fri, 18 Dec 2009 09:23:34 + > Subject: Re: [Drakelist] TR7 VFO Problem ? > > Hello all > > I have the Service Manual and have it printed out. > > To confirm the symptoms, on 21 and 28MHz the counter settles around > 33.030MHz and 17.206MHz on all other bands. Connecting an antenna I can > "hear" my signal generator on thes frequencies (sweeping the generator > through the 33 and 17MHz frequencies). With an external source the counter > works fine. > > So the synthesizer doesn't appear to be locking. I have cleaned the Molex > connectors. My next course of action is to replace the pots on the voltage > control board for multiturn ones, and re-align the voltages etc, and then > re-check the synthesizer board again. > > Thanks all for the help, so far ! > > Adrian MW1LCR > > > ___ > Drakelist mailing list > Drakelist@zerobeat.net > http://mailman.zerobeat.net/mailman/listinfo/drakelist _ New Windows 7: Find the right PC for you. Learn more. http://windows.microsoft.com/shop___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR7 VFO Problem ?
Hello all I have the Service Manual and have it printed out. To confirm the symptoms, on 21 and 28MHz the counter settles around 33.030MHz and 17.206MHz on all other bands. Connecting an antenna I can "hear" my signal generator on thes frequencies (sweeping the generator through the 33 and 17MHz frequencies). With an external source the counter works fine. So the synthesizer doesn't appear to be locking. I have cleaned the Molex connectors. My next course of action is to replace the pots on the voltage control board for multiturn ones, and re-align the voltages etc, and then re-check the synthesizer board again. Thanks all for the help, so far ! Adrian MW1LCR ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
