This amp briefly powers with blue LED but then falls into protect red LED after about 1 second. Amp draws ~8A quickly then falls to about 2A before going into protect. I was able to determine +-15v regulators are working, but now the amp goes into protect so quickly I cant get a solid read on anything else like the +-12 and +-5 supplies. I also checked Q7, Q11, Q19, Q22 and they seem to be OK. Relay clicks twice - at REM and again when going into protect.
No blown fets. TH1 is measuring about 12k. No significant DC on speaker terminals
Any clues why it might be falling quickly into protect? Any way to keep it powered so that I can locate faults?
No blown fets. TH1 is measuring about 12k. No significant DC on speaker terminals
Any clues why it might be falling quickly into protect? Any way to keep it powered so that I can locate faults?
I'd recommend replacing those 4 transistors, even if they appear to be OK.
Does removing R31 from the driver board defeat the protection circuit?
Does removing R31 from the driver board defeat the protection circuit?
Lifted R31 and the amp does power on stays out of protect, drawing 1.2A idle. What component would that correspond to? Or should I just be able to find the faults now?
Q10 is only for the protection circuit. Do you get a good drive to all output FETs with a drive signal?