My St-120 has very low (but not zero) output in one channel, and I'm hoping you can help me troubleshoot the amp. There are other threads on this topic, and I've tried most of the suggestions there. Just wondering what you would try next.
* I've tried known good tubes and the problem remains, so it's not the tubes.
* The voltages at the tube pins are all fine.
* I've checked continuity from the inputs through the attenuator to the board; that's all fine.
* The resistors on the board are all fine: same in both channels.
* I've poked around with a chopstick; can't find a problem with the solder joints.
I've ordered a new LM334, since that turned out to be the problem for someone else who had this symptom. Will replace that when the part arrives. Is there something else I should consider at this point? The amp has been flawless until recently, when I had a snap and a spark in one KT-120 that took out a 10 Ohm resistor in the now-bad channel. I replaced the resistor (and the tubes on that side) and things seemed OK, but it's possible that that did some damage elsewhere in the circuit.
Thanks in advance,