Battery won't charge

I replaced the automatic serpent belt tensioner and now the battery won't charge :banghead: What could possibly be wrong now? :screwy: The car ran fine until I parked it for 5 days and then did the repairs. What part of the electrical system am I missing? I don't think it's the alternator because that was new just a few years ago. I have had the car since brand new and it has been well maintained.

Remove and have the alt. tested the diodes can just go that quick.

Indeed I had a new alternator installed at GM a few years ago...in fact it was a rebuilt by GM...and the problem at the was not the alternator, it was the A/C compressor bearing...all on garantee ...anyway.....and then this alternator quit twice after that for no reason at all: the diode bank failed one year..I changed it for $30. and the replacement diode bank (BOSCH) was a much much better product than the original POS; and about 15 months later, the regulator (built-in the alternator) failed too. $30 (all CDN) again but you have to master the soldering gun.