[Kurt in NJ]

Yes, disconnecting the battery causes a voltage spike, this can damage alternator----the alternators are quite fixable, parts are cheap , the rebuilder I used to get parts from said that they were the best alternator ever made ---easy to fix, cheap parts, and last just long enough that the repeat customer isn't pissed off

If you can check diodes with voltmeter you should be able to test everything but the regulator---that you replace ---you will need a paperclip to hold the brushes in to put it together----