Car wont start, and then will start - Alternator?

[fatboy19972001]

I've got a '96 P10. The other day it wouldn't start after a routine 20 minute trip. When AAA got there the car started right away. So I took it to my mechanic and the car tested completely fine. A week later, I was driving to work, then I heard a pop through the radio. I turned the radio off, but I could hear a whine through the speakers that went up and down with engine rpm. The motor then cut off five minutes later. Afterwards, I turned the key and it started right up.

My mechanic thinks it's the alternator going bad, but he's reccommending that I wait until it fails, since these things can be tricky.

Any thoughts?

[nissantech]

When the car wont start, disconnect the alternator. If it is faulty the car should start straigt away.

[fatboy19972001]

Thanks