Is there anything to check for if that's what caused it to go into protect mode? At some point I may have it fixed, but I don't need to at this point.
It may have a shorted power transistor. It doesn't seem too bad off because it's not blowing fuses, so it may be a blown driver transistor only.
There is a slight chance that one of the solder-in low voltage fuses is either blown, or the shock of falling cause it to contact the metal fan box (or the fuses touched each other) that surrounds the main heat sinks. Those fuses are near the fan on the right if you're looking at the front of the amp. If one of those fuses blows, the power amp protection runs off of a backup supply so that the amp won't fail catastrophically, which would be why the amp seems to try starting up.
There is a protection circuit that detects the fan's operation and will shut the amp down if the fan is damaged. You say the fan works, so I doubt that's the problem. You can stop the fan from turning, or unplug the fan, and the amp will go into protect mode, for example.
I don't recommend trying to repair any of this stuff BTW.