I have a '73 F33A and after going to my last maintenance inspection I decided to send my alternator in to be checked out. It ended up being a full rebuild. After it was reinstalled it worked fine the first trip around the pattern until landing when it shut down, then restarted once I idled down. I then flew 60 miles to another airport and it shut down again shortly after takeoff.
I could turn off the alt switch for a few minutes, and then turn it back on and it would charge for about 5 to 10 seconds. It would hold voltage at 13.9V and amperage would spike up to about 25 amps, then reduce down to about 15 amps at an expected rate, then drop off to negative. When I landed it charged fine while I was idling at 8 amps, but kicked back off when I got in the air, (maybe during takeoff). The A & P marked the wires and is pretty confident he installed them correctly. The voltage never spikes, I have an MVP-50 and the voltage reads 13.9 when the alternator is charging. I didn't have any charging problems before the rebuild.