What is the drive signal going to the gates of those outputs when the transistors fail/overheat?
How quickly do they fail if tightly clamped to the heatsink?
What was the current draw from the 12v power supply when they failed?
How quickly do they fail if tightly clamped to the heatsink?
What was the current draw from the 12v power supply when they failed?
I retired the L2 and they do not fail any more I have verified the transistors Q25 and Q27 and they do not have leaks I am sure that if I replace the L2 they will fail but they are expensive in my country these mosfets. What else should I check?
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The numbers posted in #3 can't cause the FETs to fail since the FET is fully off.
It's unlikely that the inductor can cause the FETs to fail with no drive (post #3 shows no drive).
Q25/27 can't cause the FETs to fail.
Remove all 4 outputs. Do you have a drive signal on the gate pads of the FETs?
It's unlikely that the inductor can cause the FETs to fail with no drive (post #3 shows no drive).
Q25/27 can't cause the FETs to fail.
Remove all 4 outputs. Do you have a drive signal on the gate pads of the FETs?
I don't know what you're checking. To check the drive signal with a multimeter, you measure with the black probe on the source and the red on the gate pad.
Do you have a scope?
Do you have a scope?
It is quite strange from the Q55 and Q56 there are -69 volts I do not understand why, but that's the way I did it and in the collectors of these transistors
Remove all 4 outputs. Measure the DC voltage on Q701 and Q703. Black on pad 3, red on pad 1.
Post the voltages.
Post the voltages.
92kHz seems OK.
The drive votlage seems OK... as it can without a scope and not knowing that meter.
With nothing connected to the amp, what's the resistance between the positive and negative speaker terminals?
The drive votlage seems OK... as it can without a scope and not knowing that meter.
With nothing connected to the amp, what's the resistance between the positive and negative speaker terminals?
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