Bridge Q55 collector to emitter to keep the 3525 on (sorry I missed this). Be careful in case the amp draws excessive current.
Does the right channel produce clean audio?
If there is no bias voltage to the output stage, lift Q44.
Does the right channel produce clean audio?
If there is no bias voltage to the output stage, lift Q44.
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Hi Perry, I took your advice and jumpered the Q55. The amplifier turns on (obviously without rem as it bypasses the MCU) and I read all the voltages. I discovered a 560 Ohm resistor 1% out of tolerance and two transistors (BC846B and BC856B) also out of tolerance (in the blown channel). I removed them and I obtain a voltage of 55V between drain and source of the N channel FETs, and 52V for the P channel FET. In the working channel however, on both FETs (N and P) I measure a precise 53V, i.e. the correct rail voltage . I imagine the problem with these voltages now is the lack of these components that I removed. As soon as they arrive I'll see if the amp finally comes out of protection.
On leg 3 of the P-channel, you should have positive rail. On leg 3 of the N-channel, you should have negative rail. With a speaker or dummy load on the speaker terminals, you should read 0v on all of the drain legs for all of the outputs and 0v across that dummy load.