How to repair weak distorted channel Realistic SA 1000 home stereo amplifier D-Lab

Purchased the little jewel of an amp on ebay. Seller was honest, stating that it had a bad channel, true. I was impressed of it’s great cosmetic condition and thought, what a super Youtube presentation. So, here it is! After verifying the fault, it reminded me of vintage tube amp repairs, so I decided to change out all of the main amp caps, hopefully remedying the issue without troubleshooting! It worked! I was happy and a bit shocked. Now I see some similarities between early solid state vrs tube circuits. I plan to feature more of these shoot from the hip approaches.