Buying used gear is a conundrum unless one one or one’s friends’ have the skills to get it fixed in case it develops an issue. But on the whole, buying used is a great money saver, even factoring in a miss now and then.
I feel for @parkergetdean even if I don’t understand why he won’t just leave the darn thing on 24/7. That’s the $0 fix (well, there’s the cost of electricity, but that amp’s idle wattage is probably low).
Next best is to have it fixed. It’s a nice amp, not a NAD throwaway; it definitely deserves fixing. Here’s hoping your new tech is both smart and fair. On the bright side, protection circuitry in amps of that vintage tends to be pretty simple.

