If it does not turn out to be external wiring having been baked by heat, I would then question the brushes.
My experience the internal regulator either works or doesn't.
I have yet to see a remanufactured alternator with new brushes in it.
If the brushes are worn, they impose quite a load on the regulator.


Cheers, Charlie
If It ain't broke, Modify it!
87 Montero turbo Converted back in Spring1989
95 Montero SR 3.8 DOHC Only one?
93 Pajero 3 door 6G75 Mivec with paddle shifted 5 speed
Then a Gen2 SR with full coil independent suspension.