hI Folks, The amp went from working fine to not working at all. After cleaning the master vol pot I got sound back. The CH B "level" pot turned out to have a cracked wafer but would work starting about a third of the way up. According to the schematic I have the bass/mid/treble/level pots are all the same, 100K. They are all numbered the same. So I exchanged the damaged level pot for a good bass pot. So far so good, both pots appear to be working ok.
Now the amp will not put out a clean signal to the speaker. At the lowest setting on the "drive "pot the amp sputters and cuts out. If i crank up the volumea bit I get massive distortion, A / B or both channels.
Taking the preamp out from the master fx section yields a clean bass signal. Amplifying a master section line in acts the same as the guitar inputs, totaly blown out with distortion , sputtering and cutting of notes at low level. I'm thinking the problem is on the output board. There is plenty of output level at the speaker, just distorted.
Can anyone point me in the direction of a possible culprit. I have experience fixing amps, but I'm still learning.
I also cleaned all the pots/ ins/outs and resoldered any suspicious joints. thanks Drew
