Hi... I was getting ready to put my T/O R500 back in it's case after re-capping it and upgrading the electrolytics and swapping out the selenium rectifier with a diode etc. -- the set was working perfectly. I powered it up to be sure all was well, when suddenly the audio became awfully distorted on all bands. Never had distortion previously.

I poked around inside the chassis with an wooden pencil and tapped on a resistor (47 meg ohm in the 1U5 det amp circuit... when the audio got real loud and the distortion disappeared. I jiggled it a bit and powered back up and all seems fine now. I couldn't get the problem to repeat itself. The resistor checks fine. What's up with that?

Could be a bad ground on the tube socket. Also could be that resistor is connected to the IF transformer. Poor connection there too. I would at least resolder things around the point in question.

:Hi... I was getting ready to put my T/O R500 back in it's case after re-capping it and upgrading the electrolytics and swapping out the selenium rectifier with a diode etc. -- the set was working perfectly. I powered it up to be sure all was well, when suddenly the audio became awfully distorted on all bands. Never had distortion previously.
:
:I poked around inside the chassis with an wooden pencil and tapped on a resistor (47 meg ohm in the 1U5 det amp circuit... when the audio got real loud and the distortion disappeared. I jiggled it a bit and powered back up and all seems fine now. I couldn't get the problem to repeat itself. The resistor checks fine. What's up with that?
:
:One of my weird experiences with distortion was a radio that sounded like the audio being transmitted was a person gargling. This gargling affect even occurred when injecting a test signal. After days of troubleshooting to no affect, it was pointed out that my method of injecting the signal resulted in an open antenna loop. Re-connecting the antenna solved my problem. Perhaps you have an intermittent antenna connection?

Hi

I didn't check the schematic but are you sure it's 47 Meg? That's a very high resistance. If grid resistor try a lower value, 10 to 22 meg.

Norm

::Hi... I was getting ready to put my T/O R500 back in it's case after re-capping it and upgrading the electrolytics and swapping out the selenium rectifier with a diode etc. -- the set was working perfectly. I powered it up to be sure all was well, when suddenly the audio became awfully distorted on all bands. Never had distortion previously.
::
::I poked around inside the chassis with an wooden pencil and tapped on a resistor (47 meg ohm in the 1U5 det amp circuit... when the audio got real loud and the distortion disappeared. I jiggled it a bit and powered back up and all seems fine now. I couldn't get the problem to repeat itself. The resistor checks fine. What's up with that?
::
::One of my weird experiences with distortion was a radio that sounded like the audio being transmitted was a person gargling. This gargling affect even occurred when injecting a test signal. After days of troubleshooting to no affect, it was pointed out that my method of injecting the signal resulted in an open antenna loop. Re-connecting the antenna solved my problem. Perhaps you have an intermittent antenna connection?

Norm, you're right it's a 4.7 meg. (yellow, purple, green) When I touched this resistor with a pencil eraser the audio increased and the distortion disappeared. Just previously I had replaced the .022 cap on pin 3. It's playing OK now.

Checking the antenna as you suggest is a good idea as well as reheating the solder joints as Warren suggested. Thanks!