Working on an NAD2275 receiver amp, blown channel.
Rebuilt it and was testing and adjusting it, with light bulb limiter they even suggested using in the service manual.
Well it would randomly go nuts and light up the bulb.
At first I thought it looked like output devices shorting to heatsink, or bad connection as flexing board would cause failure.
Except it was go into high frequency oscillation when it would die.
Turned out to be a stupid little 22pf cap.
I thought they were rated for high voltage, guess not.
Rebuilt it and was testing and adjusting it, with light bulb limiter they even suggested using in the service manual.
Well it would randomly go nuts and light up the bulb.
At first I thought it looked like output devices shorting to heatsink, or bad connection as flexing board would cause failure.
Except it was go into high frequency oscillation when it would die.
Turned out to be a stupid little 22pf cap.
I thought they were rated for high voltage, guess not.
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