Powermaster alternator problems

For some reason, my amp light comes on when i start the car in the morning, and the voltage gauge is WAY down. After about 5-7 minutes of driving, the amp light goes off, and the voltage needle jumps to where is should be.
Long story short, my alternator only seems to work when its warm. anybody else have this problem?

theuser- I'm not sure what size the nut is. go to www.powermastermotorsports.com and email thier tech support. or you can call long distance 1 865-544-0115, I called earlier and the guy was friendly and more than willing to help.

scorpion, if the car is off, then the battery itself is controling the interior lights and the headlights, the alternator doesn't put out any power unless the engine is on and the alternator is spinning.

after the car has warmed (5 minutes), using a voltmeter, I get 14+volts when i rev to a fast idle (1200 rpm). when i turn the car off, the battery tests good at 12.8V.

when i first start the car, the voltmeter reads 12.4 volts, I get teh same reading when I test the terminal on the alternator also.

I spoke with powermaster tech support, and he says its a contact, or circuit, or something in the internal regular. he figures something is stuck and when the alternator finally heats up, it un-sticks, or opens the circuit. (he was more technical about it, but you get the idea.)

anyone know if they sell replacement internal regulators, or if the alternator can be repaired at all?