The only way I can use my amp is plugging in to the "Main-Amp" input on the back (basically a direct-to-speaker input, master volume is the only knob that affects anything). I want to use the tone knobs and the gain and reverb that come with the amp, but whenever I plug into either of the normal inputs no sound comes out.
I know the speaker works, I'm guessing the problem is with either the inputs themselves or in the wiring connecting the inputs to the rest of the circuit. I took the amp apart once and didn't see any cold solder joints or blown resistors/capacitors, but I'm not that experienced with electronics so I don't know if I'm looking for the right thing.
It's a solid-state amp so any professional repairs would cost more than the amp itself, so does anyone have any ideas for how to troubleshoot and repair it myself? Or do I risk breaking it entirely by messing with it any more? Thanks for any helpful answers!
P.S. If it helps, it's been in a storage room for at least 15 or 20 years.