Did we burn my voltage regulator?

[Danny Gutierrez]

  I was showing my son how to test the battery and alternator with a voltmeter.  Everything was going fine till I asked him to test the voltage regulator.  It made a small pop and the voltage dropped to nothing.  I'm assuming he touched both leads to both sides of the regulator (green and blue wires) instead of one to the green side and one to a ground.  Now the car will run but the amp gauge stays in the negative even at higher RPM.  I switched in an old regulator I had lying around and now the amp gauge stays slightly in the positive side!  Do I need a new regulator?  The fried one was an FBO unit and the one on the car now is an off the shelf unit.  I also have a regulator with a bunch of copper coils on the backside of the unit.  It's never been used but I'm afraid to try it since I'm sure it's the old points type. 

[Chryco Psycho]

more likely the alt popped a diode

[Arthu®]

more likely the alt popped a diode

I agree, sounds a lot like the problem a friend with a 71 is having. We chased the problem to be in the alternator and most like a diode problem.

Arthur

[Silver R/T]

how do you fix that, you need new alternator?