Quote from: tonyharker on August 23, 2011, 06:45:06 AM
Managed to trace out the power amp circuit - attached. Note no thermal compensation. Circuit common arrangement for the time. Must have been thousands built of similar design used in disco amps etc. I've repaired a few.
Also photographed the front and rear of the power stage PCB. Repairs appear to be consistent with overheating failures Probably more than once - tracks lifted etc.
Found final examination sticker on Preamp board - March 1984.
Will trace out Preamp next.
Tony
the power transitors are indeed 2N3055's as I have one myself and just checked them