Weak channel Rockford Fosgate Punch 30


2016-03-04 2:24 am
So I have a vintage 1991 Rockford Fosgate punch 30 amplifier that has been sitting unused in a box in my garage for about 20yrs. Prior to that, it was in a car I had for about 6yrs, and worked perfectly back then. I recently installed it and noticed that it has a weak channel. One side sounds great. The other side is much lower volume, and doesn't sound as clear or tight. To get the two sides balanced, I have to turn the gain on one up to almost the max, with the other channel at or near minimum.

I have verified that the issue is in the amplifier, and not in the signal or wiring or speakers. I opened it up and looked for obvious signs of damage, cracked solder joints or corrosion, and didn't see anything. I'm an Mechanical Engineer, but I'm a bit rusty on my electronics. I have a DMM, but no oscilloscope.

There aren't very many components inside this amp, and I have repaired this sort of thing before, but I'm a bit lost as to how to diagnose it.

Any guidance on how to go about diagnosing a functional but weak channel?

Any help is greatly appreciated. I'd like to get this amp functional since it is period correct for the car I'm restoring, and it is kind of an old friend.

Thanks, Chris