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Hey everyone,
New forum member here! I recently rescued an old teal-stripe Peavey Express 112 combo off the street. I get no sound, unless I crank the lead channel to max - then I can just barely hear a heavily distorted guitar tone. Plugging into the FX return gets me loud and clear amplification of a line signal, making me think that the power amp is fine. Everything looks fine - no swollen caps or visibly burnt-up resistors/etc. I cleaned all of the pots with deoxit, no crackle/etc. I pulled the board out and nothing looks bad underneath.
While I had the board out of the chassis, I added a socket for the one op-amp that had none. I powered it up before I fastened down all of the pots and jacks and I was able to get intermittent sound out of the amp! It cut in and out if I touched anything, making me think it was shorting/grounding. So I tightened it up and... it was right back to no sound.
Now I'm confused. I'm thinking I'll start checking if any pots or jacks are shorting to ground somehow? Anyone see this kind of behavior before? What would you do next?
Thanks!
P.S. Who is me? I kinda know a little of what I'm doing, but I'm no engineer. I took electronics at a vocational HS in the late 90's, and I tinker/make stuff/fix stuff and teach kids "maker" skills. I play guitar/bass and dabble in production, but am way more into making/fixing gear than I am in being a competent musician.
New forum member here! I recently rescued an old teal-stripe Peavey Express 112 combo off the street. I get no sound, unless I crank the lead channel to max - then I can just barely hear a heavily distorted guitar tone. Plugging into the FX return gets me loud and clear amplification of a line signal, making me think that the power amp is fine. Everything looks fine - no swollen caps or visibly burnt-up resistors/etc. I cleaned all of the pots with deoxit, no crackle/etc. I pulled the board out and nothing looks bad underneath.
While I had the board out of the chassis, I added a socket for the one op-amp that had none. I powered it up before I fastened down all of the pots and jacks and I was able to get intermittent sound out of the amp! It cut in and out if I touched anything, making me think it was shorting/grounding. So I tightened it up and... it was right back to no sound.
Now I'm confused. I'm thinking I'll start checking if any pots or jacks are shorting to ground somehow? Anyone see this kind of behavior before? What would you do next?
Thanks!
P.S. Who is me? I kinda know a little of what I'm doing, but I'm no engineer. I took electronics at a vocational HS in the late 90's, and I tinker/make stuff/fix stuff and teach kids "maker" skills. I play guitar/bass and dabble in production, but am way more into making/fixing gear than I am in being a competent musician.
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