Bonanza Alternator Light

Does anybody know about some quirkiness in the alternator 'idiot light'
indicator? In my F-33A, it'll come on for a few seconds and extinguish. I've
had it looked at twice...nothing loose, everything checks out fine, battery
is charging and holding charge. But a couple of times in flight, it has come
on and before I can do the manual reset, it goes out. Happened twice on the
ground during run-up but manual reets worked. Anybody?

Peter Shurman
Bonanza F-33A C/GRDT
Toronto, ON