Just to update, I'm still in the thick of trying to figure this amp out.
I replaced one transistor (Q16) that was reading faulty, plugged in the amp, and blew the fuse closest to the filter caps.
At this point I decided to replace most of the transistors on the board (everything that the local electronic supply store had in stock) and stick a new fuse in.
Powering up, I no longer get signal from the guitar, but a very loud hum from the speaker, even with nothing plugged into the input. There's a chance I didn't solder in all the new transistors correctly, so I'll double-check that.
I decided to check values on the board for resistors and diodes. One of the rectifier diodes is reading short, so that could be causing the hum in the speaker (I think??).
The .33 ohm cement resistors all give a value of "0". The undersides are a little crusty. Some of the other cement resistors read true to the printed values.
The smaller resistors on the board give mostly good values, but some are well over their range, and some are seriously outside tolerance or read 0.
I guess something happened that fried these resistors. Really scratching my head and hoping to not have to replace all parts on the circuit board. I assume I should replace all resistors outside their values with new ones, and see how it does from there.
Does anyone know a good tech in Atlanta who could quickly troubleshoot/fix this thing for me? The tube amp guys don't touch solid state amps...
