I think I figured out the problem from the second repair attempt. My replacement bias trimmer was set fully counterclockwise, as the manual states, but it read 5K ohm between base and collector with the bias transistor removed!! I corrected the orientation compared to my first picture! I'm going to order new power transistors tomorrow. This should be it! Wish me luck.
What type of blue goo should I use to secure the transistor to the heat sinks? It looks like Locktite of some sort.
What type of blue goo should I use to secure the transistor to the heat sinks? It looks like Locktite of some sort.
I got it up and working! It sounds great. It's a really laid back sound, like vacuum tube amps. The highs are really smooth and I don't get listening fatigue from it. I think it might have to do with the high impedance input.
How close should power transistors be matched? Right now, I've got them differing between 19mA and 27mA across the emitter resistors in the power section. I might try replacing the 19mA transistor tomorrow with another from the same batch.
How close should power transistors be matched? Right now, I've got them differing between 19mA and 27mA across the emitter resistors in the power section. I might try replacing the 19mA transistor tomorrow with another from the same batch.