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How do you determine that your final tubes are near EOL? Currently when I tune up my T-4XC, particularly when I peak the "Load" control I have to perform this really quickly to get a peak, because iP

Thanks, Jim. It isn't critical for me. I'm just wondering with the end goal of making a similar receiving-only tuner for non-ham bands. Barry - N4BUQ

I reckon that if the sideband selection was fully in-line with the reality of our conventions that they wouldn’t have needed the lamps and we would be simply selecting manually — like with the

Thanks for that clarification! This is what I was looking for. Barry - N4BUQ

Next time I have the L4B apart, I will measure the uh on? 80-10m.? ?Then add it to my notes.? ?I did measure the plate choke in one of my L4B's and it's 154? uh.? ? ?Then also put it on the

The 50k oscillator is solid state, so likely not a tube issue. Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from [Proton Mail](https://proton.me/mail/home) for iOS

Actually, there is no TUNE position on a TR3/4. One uses CW for tuning. Then, when going on SSB, use the SIDEBAND switch to select the proper sideband. The indicator should not be interpreted as

An even simpler soft start is to add inside the PS7 a NTC inrush limiter as found in every SMPS nowdays. /g/DRAKE-RADIO/files/TR-7/PS7-Inrush.pdf "atlasstuff via groups.io"

Glenn, Mine is another vote for never looping the AC primary circuit into a transceiver. I had a similar idea to you. As the PS7 has no mains on/off switch of it's own, I thought I would get hold of a

Just a thought for a simple option but not that smart. I have a few tube KW Electronics transceivers (in addition to Drakes). Two were bought with an on off switch on the power supply unit, being home

Very insightful Gary. I really appreciate this education. That is why I enjoy getting my hands dirty in these vintage rigs. 73. -- Joe - W7BWA Custer, WA

OK, in this case, antenna for calibrator - but the gimmick story is still true.. A d using this as an antenna still counts as a “gimmick” in my book. It takes the place of a capacitor that could

That is what was known as a “gimmick”. This was a way to tweak a circuit to work. Often they had two wires wrapped around each other, each end being tied to a circuit point. The calibration

Barry. You have saved my bacon and I am so grateful. I spent hours trying to track this down. Thanks so much! I’m really not that dumb! Lol interesting on the filters. I will search it out and if I

It serves as the antenna for the calibrator signal. ?Not sure why Drake did it that way. It’s confused many in the past including myself. Good luck with the TR-3. I have two of them. My favorite

*WARNING:? I am a hobbyist and I am learning vintage radios. I can usually find my way around schematics to some degree, but not well. I do better with service manuals and I've not found any for

Let's make this easy. Pull the board and out it on your bench. Connect 10 volts to pin 11/38 and ground to 11/11. Make your measurements with and without the transistor on the board. Verify the pinout

There is no Zener in the PTO schematic you posted. :D "VE7PS via groups.io" <ve7ps@...> wrote: -- 73 -Jim NU0C

US Patent 4237521, conveniently stored in the group Files section for your viewing pleasure. /g/DRAKE-RADIO/files/TR-7/US4237521.pdf I proved experimentally some years ago that the

Check the 50 kHz LO injection into the product detector and the second mixer. This is not a typical failure. Rob, NC0B