Alternator Help?

[dreddy]

Gentlemen,

The alternator in my 85 911 gave it up about a month ago. I took it in to the local refurb shop who exchanged it for a rebuilt unit rather than fixing mine. They said that damage to the windings indicated that the battery was not accepting a charge and it should be changed as well. Finally got the Optima battery (based on forum reading) and the rebuilt alternator installed tonight. The car started right up without hesitation, no alternator light on, checked voltages, everything was looking good. I turned everything off to finish tightening things up, put the AC belt back on and now... alternator light on, voltages seem to indicate that no charging is happening. For the few moments that everything seemed to be working the battery voltage was 12.8V while running, now it is about 11.6. I can't understand what could have changed. I began to 2nd guess my alternator connections because they are the only thing that I cant' see so pulled the fan and housing back off to check. everything looks tight and correct. 12.2 V between the ground and B+ terminal (same as between the battery terminals) and less than an ohm from the ground terminal to anything else that is grounded. I don't know what to look for in the 3rd connection.

My best guess is that the rebuilt alternator had an infant mortality but I wouldn't take that guess to Vegas. Is it possible that putting the AC belt on and turning the compressor caused the alternator to blow out? Seems very unlikely.

Any ideas would be appreciated.

Thanks in advance.