Re: [Drakelist] TR-7 Board History and head scratching
Thanks Jim, Oh, and one board has the "called for" 2.7k resistor to ground on the 25v line, and the other one has a 7k resistor that looks original. None of my schematics show any change called for. Changing out the caps might be a good idea. David Wd9cmd - Original Message - From: "Jim Shorney" To: Sent: Monday, January 12, 2009 9:21 PM Subject: Re: [Drakelist] TR-7 Board History and head scratching Hi David, On Mon, 12 Jan 2009 20:43:46 -0500, David & Chris Drake wrote: Looking for some historical information on Drake TR-7 boards. Welcome to the world of undocumented changes. User information like what you have provided helps add data points for the collective. All this started because during an alignment, I could'nt get the required voltage on the VCO board, (shy by around 1-1.5v) and found I only had 22 volts going in instead of 24-25v. I can't answer your specific questions about the board changes, but I would recommend replacing the electrolytic caps on the PS boards - expecially C2108. They are getting old, and strange things can happen as they go bad. 73 -Jim -- Ham Radio NU0C TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! 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 mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR-7 Board History and head scratching
Hi David, On Mon, 12 Jan 2009 20:43:46 -0500, David & Chris Drake wrote: >Looking for some historical information on Drake TR-7 boards. Welcome to the world of undocumented changes. User information like what you have provided helps add data points for the collective. >All this started because during an alignment, I could'nt get the required >voltage on the VCO board, (shy by around 1-1.5v) and found I only had 22 volts >going in instead of 24-25v. I can't answer your specific questions about the board changes, but I would recommend replacing the electrolytic caps on the PS boards - expecially C2108. They are getting old, and strange things can happen as they go bad. 73 -Jim -- Ham Radio NU0C TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! 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] TR-7 Board History and head scratching
Hi to all, Looking for some historical information on Drake TR-7 boards. I have before me two DR-7 boards, one being green, and labeled C-3849 R. The second board is beige in color and looks to be a bit better quality. It is labeled C-3849 W. I also see that the circuitry is slightly different. Is the W a newer board? Next up, the power supply boards. Also have two before me, both green, one labeled B-3970 L and the other is B-3970 W. Again, the circuitry is slightly different. The later has a 0.05 ceramic cap bridgeing the center taps of the two onboard transistors. The L board has the same cap, but , its on the circuit board. Both have additional resistors on the bottom across R2129 and R2130. On the W board these appear to be 66 ohm each (if my eyes are seeing correct). The L board has resistors in the same position and these are 68 ohm resistors (ok, close). By the schematic, (and I have both the original 78 manual and the 80 revised editions), these two "on board" resistors should be 15 ohms. Checking both boards, (I did'nt pull the resistors to check their value), they are in fact marked 15 ohm and are carbon comp. Simple calculations net out just a shade over 12 ohms equivalent. I realize its not a big difference, but why was it done? Increase the current to the T-2101 Transformer? Which in turn would raise the voltage on the 25v line? So, the questions are, 1) Whats the history in the labeling, and 2) Are the bridging resistors on the underside of both power supply boards factory wiring? All this started because during an alignment, I could'nt get the required voltage on the VCO board, (shy by around 1-1.5v) and found I only had 22 volts going in instead of 24-25v. Thanks in advance for your input. David Wd9cmd___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Dirty chassis b-line
I have an r-4b and t-4xb which I was going to try to clean up (the chassis are REALLY dirty). The fronts are pretty good but the problem is the dial ring on the r-4b is faded to a dark yellow on one end of the dial rotation. I am pretty sure there is no way to solve this so I think I may use these for parts and look for another. (cleaning these up is a bit beyond my abilities) If anyone has an r-4b for sale please contact me. It doesn't have to be perfect but should be fair cosmetically and good electrically. I just missed out on a r-4b listed on eHam darn it. Keith Hamilton tu...@zoominternet.net ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] microphone bass boost
Hi John, I guess one of the questions I'd also be thinking about is whether the filter alignment (10V regulator board) is correctly adjusted. If the filter skirts are set to cut off low frequency voice tones (yours), the radio's alignment could be hurting your chances. One way to get an idea is to use the passband tuning to adjust the voices you receive until you hear low frequency response like you'd like to have. Then compare that setting by turning the passband tuning on and off. If there's a big difference, your rig might benefit from realigning the passband control pots on the 10V regulator board - after verifying that the board is putting out 10.0 VDC, with a known accurate volt meter. 73, Bob, KD7NM PS: I sent you a direct email last week, and resent it this morning, expressing interest in the 1500 Hz C-Line filter, bur didn't find a response. > _ > From: drakelist-boun...@zerobeat.net > [mailto:drakelist-boun...@zerobeat.net] On Behalf Of John Stringer > Sent: Monday, January 12, 2009 9:10 AM > To: drakelist@zerobeat.net > Subject: [Drakelist] microphone bass boost > > My voice has virtually no bass in it and I am told my transmit signal from > my TR7 plus Drake 7077 microphone is too high pitched. Can someone help > me with a simple circuit to boost bass output from the microphone or offer > me other suggestions to solve the problem?John. GI3KDR <>___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] microphone bass boost
My voice has virtually no bass in it and I am told my transmit signal from my TR7 plus Drake 7077 microphone is too high pitched. Can someone help me with a simple circuit to boost bass output from the microphone or offer me other suggestions to solve the problem?John. GI3KDR. <>___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake QSO
For all that may be interested, here's the announcement from CX for the vintage radio contests upcoming; http://www.qsl.asti.com/CX/Feb2009announcement.html A good way to have some fun with the Drakes !! Thanks, David Wd9cmd - Original Message - From: Rick Tucker To: drakelist@zerobeat.net Sent: Monday, January 12, 2009 8:50 AM Subject: [Drakelist] Drake QSO I had just finished going through my C-line and cleaning everything including switches and buttoning it back up. I set it up in my operating position and after warm up put out a CQ on 80 cw. W0CCA, in western CO came back and we had a long rag chew. Cap was running his Drake B line. What a pleasant coincidence. Couldn't have planned it better. Cap and I also use Drake R4A or B with DX 60s for some cw work. Rick W0RT -- ___ 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] Drake QSO
Rick, As info, you can put the "tubers" to good use on CW in a couple weeks, and SSB/AM in February. Classic Exchange or "CX" is sponsoring contests twice per year for antique or nostalgia radios. You receive a 'multiplier' for the age of the equipement used. See the Arrl Website for details at : http://www.arrl.org/news/features/2009/01/09/10557/?nc=1 Have fun with those Drakes !! David Wd9cmd - Original Message - From: Rick Tucker To: drakelist@zerobeat.net Sent: Monday, January 12, 2009 8:50 AM Subject: [Drakelist] Drake QSO I had just finished going through my C-line and cleaning everything including switches and buttoning it back up. I set it up in my operating position and after warm up put out a CQ on 80 cw. W0CCA, in western CO came back and we had a long rag chew. Cap was running his Drake B line. What a pleasant coincidence. Couldn't have planned it better. Cap and I also use Drake R4A or B with DX 60s for some cw work. Rick W0RT -- ___ 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] Drake QSO
I had just finished going through my C-line and cleaning everything including switches and buttoning it back up. I set it up in my operating position and after warm up put out a CQ on 80 cw. W0CCA, in western CO came back and we had a long rag chew. Cap was running his Drake B line. What a pleasant coincidence. Couldn't have planned it better. Cap and I also use Drake R4A or B with DX 60s for some cw work. Rick W0RT___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
