I've just found this technics amp in a skip, I'd say mid 80s vintage.,
along with the rest of the system! :-)

The amp only outputs at very low volume - and then for a short while.
Also if you push it up more than 3, it cuts out and needs a power
cycle. Both channels are affected. I noticed R701, 702 (470R)and D701,
702 (Bzv85c) get very hot and there is evidence of some scorching on
the pcb. Might change those diodes.

It uses an STK 4152 II, pretty typical design of the period.

The headphone o/p works normally.

Any suggestions before I go on a cap change oin the o/p stage? anyone
have a schematic?
cheers
B.