If it's the alternator, you can decide between overhaul or repair as needed. Either way, you could pull it apart to see what's wrong with it before sending it out.
If it was a car alternator, I'd take out the brushes to see if they were too worn and not making contact anymore. They're so cheap (and I once got stuck in the middle of the Arizona desert towing an airplane wreck), that I replace them every 60,000 miles as a preventative measure on my cars. A few years back, just to see, I took some aircraft alternator brushes into a local shop and was handed a new pair for $3.58. Since it was an experimental aircraft, that was a cheap repair.
