Help: my DR squeals when I turn the reverb knob

6/14/2000 8:45 PM

Carl

Help: my DR squeals when I turn the reverb knob I just did some work on my 1965 BF DR, and it works fine now except I get a very loud, constant squeal when I turn the reverb knob up to 4. I took the V3 reverb tube out (it still does it) and disconnnected the reverb input/output cables (still does it).     Here is the work I did to the amp. I replaced the power filter caps and resistors in the pan, replaced the bias cap and resistor, replaced the screen resistors on the power tubes, replaced the 25/25 electrolitics on the board, replaced the one chocolate drop coupling cap on the board but left the original blue ones alone, and I replaced all the resistors on the board with allen-bradley carbon comps. I did not move any wires that I know of and I have not done anything to the pots. I did snip what looked like a resistor lead end that was dangling off the reverb output (or maybe input) jack that was barely touching the chassis before I had this problem.     I looked at the schematic, and it looks like I did everything right. Last night, I even replaced the 25/25 electrlitics on V3 and it did not help. I then disconnected all the wires on the tube side of the board and lifted it up to see if any solder had run to where it did not belong (it had not). I feel it has something to do with a capacitor, but I don't know which one could be causing the problem. I may replace the disk caps that are on the reverb channel (maybe one got hot while I was soldering around it and is now leaking). I would appreciate any ideas.     Thanks,     Carl