This unit was used with a bench power supply, so the stock power supply has never been powered-up except to verify operation.  The amplifier was never pushed hard, just played occasional music for thirty minutes to an hour at a time maybe a once or twice a week.  Works like new, no dings or scratches or anything.  I have two of these listed, they were purchased a few months apart and came with slight variations in power supply, so I've listed them separately.  The amplifiers look identical, the only variation is the power supply.