A NAD C355BEE integrated amplifier came into us for repair last week, with the customer reporting that the amp would remain in standby at all times - this is a common fault when the output stages have been destroyed, usually by short circuit load or high volume use for prolonged period (thermal runnaway).
Having got hold of the circuit diagram, it was easy to diagnose the problem armed with just a continuity tester - the PNP output transistor on the right channel was short circuit from collector to emitter, which had then blown the DC power supply fuses. His caused the output voltage of that channel to be stuck hard against the
