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Does the signal meter still work on TX and if so does it read the same as the radio warms up? Check the squelch when it's cold (with no signal) and note on the knob rotation where it just squelches the static. Does that squelch point change as the radio warms up? The S-meter and the squelch...

Yes, on that circuit C25 has the + going to ground. It's because there is a negative voltage with respect to ground happening there.

Kenwood Mic Pinout: 1 - Mic Audio 2 - STBY (PTT) 3 - Down 4 - Up 5 - +8V 6 - NC 7 - GND (Mic) 8 - GND (STBY) 636: 1 - white 2 - red 7 - shield 8 - blue

Didn't you post this the other day?

That is equivalent to the "Load" for the driver section when the amp is on "high". I guess one might call it a Cathode tune but electrically it's on the output side of the tapped driver tank coil. D&A put the "Tune" cap for the driver section on the front but probably for space reasons (and the...

It's a split rail supply with +9V and -9V on each side of ground. It could be done with two equal 9V wall warts with the second supply wired in reverse.

♫ Well, Earl put down his bottle, mashed his foot down on the throttle, and then a couple'a boobs with a thousand cubes in a nineteen-forty-eight Peterbilt screamed to life. We woke up the chickens. ♫

It is odd that they only use a 150 volt cap but it's not a component that fails very often on D&A amps. When I replace one I always use a 10uF - 450V just because. Caps are inexpensive so might as well upgrade it when replacing.

The negative goes to pin 5 and the plus through the SSB switch to the hot side of the relay. Here is the Raider:

Clean!

"Short" 6LF6 tubes are all but impossible to get. If your amp is designed for them finding a replacement is difficult. The 6LF6's that are available are almost always the tall ones as are the 6MH6, 6KD6 and 6KN6. "Some" of the 6KN6's are short but they have dual plates and dual filaments and...

Be careful using 6LX6 in place of other 12 pin compactrons. On a 6LX6, pin 7 is connected to the filament internally and can short out the filament supply if the socket has pin 7 grounded or used for a tie point. Some say to just cut pin 7 off and use one anyway but I have found the little nub...

I think touching your finger on C193 making the problem go away was just an unrelated coincidence. Go back to troubleshooting in and around the Balanced Modulator IC2. Check all of the DC voltages (shown in parenthesis) and see how they compare to this schematic: Pay close attention to pins 1...

Make sure any resistor you are using is non-inductive.

I think you meant MRF422, Nomad. Toshiba used to make the 2SC2510 (150W PEP) that was the 28 volt version of the 2SC2879 (100W PEP) HG is now making the 2SC2510.

Someone with HTTrack should check the IP route to see if the forum is hiding there. Strike that, I didn't see the last couple posts when I wrote this..

Like "HAM" bands? OK, since you are the authority on the subject matter, I'll just quit listening to my lying ears and concede that it's completely false because you said so. Thanks for being the arbitrator of all things audio. I'm not sure the world could exist without you, thanks.

"it sounds nice for rag chewing locally but for dx, 300hz - 2900hz audio bandwidth will take you out." This is only true if the receiving end has narrow/stock receive. When you are receiving full bandwidth, the guy with the heavy low end cuts through the high pitched transmissions almost more...

Neat looking old radio!

There are so many different configurations on D&A amps for the "low" side. Some have a relay that bypasses the output tubes and runs just the drivers on low. Others (even ones that don't have the "250" switch) run all the tubes but cut the plate voltage in half for low side. Many times over the...