2 hours ago, northernz said:

 So....intermittent problem?

Loose S.  If it's in the harness it will still be there with the new/reman alternator.  Loose L might do it also.  No winding current means no charging.  The loose parts could be inside the alternator.  Guess you'll find out.  Those studs in to, through, the case can come loose.  When you remove it, shake it hard and see if anything rattles.

Just an update, got my new Alternator from Rock Auto, turned out its a GM part and my old new belt is too long! Quick trip to NAPA for a shorter belt and all is well, showing a good charge on the gauge and the car is running more strongly and idling better. I'm thinking that

whatever problem I had was causing a weak or intermittent spark problem.

Thanks to all who offered their input!

Mark

Cool! So it was just a bum rebuilt alternator?

Man how I hate rebuilds...