Not getting power to voltage regulator

[Z Excellence]

Got a rebuilt alternator and installed a new external voltage regulator on my 76 280Z, It worked fine for about a month. Now the alternator is working fine but not sending power to the voltage regulator. This is an intermittent problem but has left me stranded 3 times when it doesn't charge the battery.Works perfectly for a few days then stops charging the battery which I can tell by my guage on the dashboard and the dimming of lights also checked it out with a mechanic using a meter. The fuseable links under the covers by the strut towers are good. Is there an ignition relay that could be malfunctioning from time to time and where is it? Much thanks

[SteveJ]

No offense, but your problem description doesn't have enough to have people give more than wild guesses.

Have you actually gone through the diagnostics in the FSM, section EE? If so, what tests did you run and what were the results? (Pass/Fail or numbers)

Did you install the alternator with the right tension? Did you re-check the tension to make sure the alternator hasn't moved?

A lot of people seem to have their favorite "shade tree mechanic" way of doing things. In my own experience, I do better following the manual and asking for help on the occassions the manual falls short.