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