Glad to know it's not the transistors - it sounds like it's frobek's solution for you. Good luck with the SMD resistors, it shouldn't matter if they're bridged as long as that's what the circuit is doing. Hard to tell from the photos where the PCB trace is going.
In my experience with amplifiers, 90% of faults arise from components under some sort of adhesive or glue. Either the glue corrodes the component, or worse, goes conductive 😡
