I have a 1994 f150 the voltage regulator went out in the alternator. I took the alternator to a rebuild and they replaced the regulator and did full check on it. I put the alternator back on the truck after the battery was fully charged with a charger. There was a pop and some smoke from the alternator and the regulator was fried again. I have checked all of the wires and can not find any bare spots. Help would be appreciated.
Mark

 

There's not much to go wrong outside of the alternator itself; maybe the rebuilder did not connect a battery source to the alternator when the tests were run on it. If it had, then the results would have been the same as you found when you connected up the rebuilt unit.