1993 Maxima voltage regulator location??

I have a 1993 Maxima with @70,000 miles on it. The battery is dead, and I found out the charging system is only putting out just over 12 volts. Is the voltage regulator located inside the alternator, or does an electronic module control this??
Also, what is the recommended service interval for the 3.0L timing belts??

Inside the alternator and the interval is 60k I believe

Thanks muchly!!