acoustic 140 loud pops when tapped & bass pot noise

[pontiacpete]

I've been working on this amp on a current limiting bulb and it seems to have a very loud popping noise when tapped on the faceplate. First I checked all solder joints, then cleaned power transistor legs. Then,I tried narrowing down the problem to one of the pre amp boards by grounding the signal path to one then the other. I thought maybe it was some sort of microphonic noise from the transistors on the suspected board, Q101,Q102, and Q103. THat wasn't it. I, also, found both bass pots seem to interact with eachother and have a loud noise, on one when reducing the pot and on the other the same when increasing. Found that each have DC on either end. So, I thought if I changed the caps the effect the lugs on these pots the problem would be solved . Wrong again.
I went to the power amp changed c311 and c301. Still no change in pots or popping noise. Swapped out the main filter cap c401. nothing.
I'm not sure where to go from here, has anyone ever encounter these types of problems with this amp?

[gbono]

Did you resolder (remove old solder and reapply solder) all the potentiometers? The solder joints are under stress since they are the electrical AND mechanical connection - they may "look" good but just go ahead and resolder all of them.

Did you visual the input jacks too?

What about the electrolytics on the boards?

[pontiacpete]

Thanks gbono, after a lot soldering and resoldering and looking, a broken ring on a one of the input jacks was found therefore the loss of ground, problem solved.

thanks again.
pete