Regeneration power amplifier WS304

I bought this amplifier in the Internet forum. It was broken but metal case was in a very good shape. Most of those devices are badly scratched. This amplifier has very simple and well documented construction. I decided to take a risk. I bought it. When I opened it turned out that it hadn't been serviced by any amateur. All part were original. Big plus.

I have been told, by previous owner, that a problem is burning fuses. I thought it was about those from power supply circuit and I suspected power transistors to be broken. After some time spent with multimeter it turned out, that everything is ok and one fuse is really burnt. This output was shor circuit to ground. I decided to fix this problem using method of eliminating parts one after another. As one can see, there aren't many pars from this fuse to speakers.


After resoldering a few wires and cleaned up speakers mode switch, short circuit disappeared. During cleaning I found small neaked wire laying on PCB. I don't think it could caused a problem, but I'm pretty sure that can cause it in a future. Below you can find some photos from cleaning process.

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