Originally Posted by habbyguy

The problem is pretty much obvious...

What happened with the original alternator was that the "brushes" (the spring-loaded blocks that make contact with the alternator's rotor) were worn down, making poor or intermittent connections.

Then you ordered a new alternator. All good, right? Nope. The connections were different, so you swapped the old regulator onto the new alternator.

Unfortunately, the brushes are part of the regulator, so you put the only bad part from the old alternator into the new one. It worked for a very short period because of the shiny new contacts on the rotor, then gave up (it'll probably work intermittently if you continued to try to use it).

So... I'd suggest your best course of action would be to order the correct voltage regulator for your car (which presumably will fit the new alternator, since the old regulator did, even if it didn't work for long). Then, with new brushes, your alternator should work again, for a long, long time (assuming you get a quality regulator, that is).