Problem is that the 3 amp speaker fuses are blowing, also have poor audio
signal on one channel.

So far have done basic check on power transistors ... checked out okay but
hfe was only 20 or so. They are original parts ... maybe 25 years old.

Checked most of electrolytic caps in power section ... replaced one.

Replaced most, but not all of 'support transistors' in power section ... was
able to get a weak audio signal from one channel. However, raising the
volume level blew a speaker fuse.

The question now is whether to spend $40 on new power output transistors
(total of 4 ... 2SD586). Specifically, could the existing output power
transistors check out okay, with no obvious shorts, but still not produce
the rated signal power level ... and also cause a speaker fuse to blow?

Thanks ... Dave