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I tested contacts, inductance and resistance in all parts used on 40 meters only. While doing so I lifted all leads that might affect the measurements. This brought 40 meters back to life. Miracles

Besides the difficulty of selecting a quiet 6EJ7 tube, the circuit design is flawed. The earlier 6HS6 mixer has the 5695 kHz IF tuned circuit directly connected to the grid, and the LO fed to the

Please try 6BX6 in place of 6EJ7 (My injection method by LA8AK). 6BX6 has half Gm as 6EJ7, yet same pin connection. You can try 6BX6 without soldering. I would appreciate any feed-back. Yuichi JA3XKJ

The power supply that is the subject of this issue is the 7805 regulator on the VCO board. That is the one that denies power to just the one VCO (high bands, in this case) when it fails. Regards, Gary

The WB4HFN website has a section with great information related to that power supply board. I just used it to resurrect a TR7 that was DOA. Good luck. 73 Tony N5DIM

Sounds like you are on the right track. Don’t ocelot the electrolytic capacitors on that supply as well. Gary W0DVN

Gary, I found a few minutes to work on the TR7 and discovered that the high VCO is not working at all. It does have the 10 vdc supply switch on it but I don't know if that reulagor is working or not.

It seems to me that the 6EJ7 was one of the first frame grid tubes. Supposed to be magic but then turned out to have problems. -- Richard Knoppow Los Angeles WB6KBL SKCC 19998

I thought about that, but you know how difficult it is to get to that tube.? Might have been easier making the mod than swapping the tube several times.? Now guess I'll move on to the audio and

I have done this mod and it is, indeed, effective. I have found that some receivers can benefit from simply trying multiple 6EJ7’s and selecting for lowest noise. The circuit is very sensitive to

Drake TR7 s/n 369 w/ 4 filters: 6kHz, 2.3kHz, , 1.8kHz,; 500Hz; $875 & split shipping CONUS; includes nice condition & fully functional PS7; photos here: https://photos.app.goo.gl/tXKwwrBg13GmfiD17

I recently acquired a late serial R4C with no mods applied.? There was quite a bit of noise in the audio with a dummy load attached and after reading everything I could find on the subject I figured

"Jim VE7RF via groups.io" <jim.thom@...> wrote: Yes, that is all correct. This is old tech that has been around since television sets became consumer commodities and they are robustly

##? The HV probe just arrived yesterday.? ?They stipulate? that if the return lead goes open, yes, you will end up with full B+ on the

Steve, I smelt no smoke and saw no burnt resistor. As far as I can see from the schematic only the following parts are used on 40 meters: L1, T3, C4 and C7 (inside T3), T8 and T10 - and of course the

Thanks Gary and Jim. On the radio working I don't remember having it up on those two bands before but I expect it did work. In cleaning the female connectors on the VCO board I used a GUM Proxabrush

Ah yes, a Molex issue. I knew I had seen that somewhere before but did not think to check Drakelist. Another thing to do is inspect the female connectors looking into the pin holes. If you see a large

Gary- About 50mA, keying in CW mode. In Tune mode, about 90-100mA. comcast.net_at_groups.io_lastradioman@...> wrote:

Do you get idle plate current when you key the radio? Gary W0DVN

It is worth asking, did the failure of your VCO board (displaying 51.950) occur on its own? That is to ask, did the radio work properly and then just fail or has it, as long as you have had it, always