strange crackling sound from my 2000GTL

[loosecannon]

im hoping maybe someone here has had this happen before or knows what it is.

my 2000GTL emits a crackling sound when the volume is all the way down, and/or when the squelch is turned up.
the noise is still there when you turn up the volume, you just cant hear it then.

it does this regardless of whether it is being powered by the internal, or either of two external power supplies.
(also have these plugged into a tripp-lite AC voltage regulator/noise isolator. tried them into the wall with same results)

it does this with no antenna hooked up also.

i would first suspect a bad or leaky electrolytic cap, but this problem was there before, and i have since re-capped the whole radio including the freq. counter.

when i switch from clock to freq, counter; it seems to change the noise ever so slightly, and this is the only thing i have found that has any affect whatsoever on it.

i have not replaced the FET's in the freq. counter yet.
could it be these?

no, there are no rice crispys in my radio. i checked.LOL

thanks for any and all suggestions,
loosecannon

 

[DTB Radio]

no, there are no rice crispys in my radio. i checked.

That pretty much covers everything I was thinking it could be....

Actually, I'd suspect a noisy semiconductor junction someplace. You might need to uncouple various audio stages until you lose the noise, and trace it that way. Unplug the counter/clock module and see what happens, too.

 

[loosecannon]

thank you, i will try that, and post the results here.
loosecannon