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This amp came to me needing new input jacks. The jacks were intermittent. I replaced them and in the process broke a lead on the "style" switch. I replaced that switch and returned the amp in working condition to its owner. They just came back a week later w/ the amp. It has a static type of crackle only when a note is played. The crackle even rides on top of long tones. It is very elusive and comes and goes. I tapped all over this thing with the chassis out of the cab w/ no apparent loose connections. I cleaned all the pots, measured grounds from input jacks, tried a substitute cab etc... still there after all of it even with another cab. Actually I tried a PA speaker AND another bass cab and it's still there in both. I just scoped the speaker out w/ 100hz in the input. I cannot see the crackle but can hear it quite obviously. I'm lost here and any help would be GREAT.
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well I spent 4 hours on this thing... I eventually alligator clipped to ground and poked around w/ the other end at things that were at ground on the schem. When I touched the speaker out ground the crackling went away. I then went through and soldered all connections from there back to the chassis ground. It seems as though many grounds are tied to one point on the board, then that point is also where the CT of the PT is connected. So I'm assuming the CT of PT is grounded via the transformer bolts to the chassis, which I also tightened up. -
When troubleshooting I've never used the grounded alligator clip thing. Thanks for telling the method.Comment
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me neither! seems like a good option.Comment
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i am not an electronics repair person where in mich. can i get this problem corrected or can i just tighten the transformer bolts?Comment
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Well, I am in Lansing, and I have fixed an amp or two in my time...
If that is close enough for you, call me after 6:30PM - 517 882 8544Education is what you're left with after you have forgotten what you have learned.Comment
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