'06 belt squeaks, alternator replace questions

wanting some opinions on this - new belt put on today, while test driving it started to squeak intermittently (mild not full on) shortly after engine start and turning right.. while this happened i noticed the voltage drop from the usual 14.1 or so down to 12.2 12.3, smelled rubber, 10 seconds later squeaking stopped and voltage back up to normal

the tensioner and idler have been replaced, and i am now left with the alternator - going to replace, it is an '06 maybe good to do anyway as preventative maintenance. i researched the 'bracket in the way' issue with this alternator and doing it from the bottom, although couldn't find an actual how-to but seems doable for the novice. is the entire removal done from underneath or is it just to get that bracket out of the way so that the alternator bolt has a clear exit?

That is an expensive preventative maintenance when you don't even know if the alternator is toast.

fair enough.. guess i should take it out and get it tested would be better start. i just don't know what else it could be - if i lose voltage when the squeal happens but not power steering (situation described in post) that would point to the alternator or at least its bearing wouldn't it?

i pm'd petrified rabbit on this but posting here too - way back when I had the underdrive pulley installed I thought I went with a 1" shorter belt but it was only 10mm, 730. Had no problems for over a year and then some squeaks started, so thinking that 730 may have been just a bit too long... probably would have been fine in warmer climates.. so going to try 720 and 725 today hopefully, I dont even know if the 720 will clear the pulley but I seem to remember daox saying that one may have to go an inch shorter on the belt so gonna try 20mm shorter.. well see how she goes..

also in the first post of this thread i failed to mention that 'that' particular belt was a 740 which clearly would be too big seeing that the pulley is 15% shorter in diameter

so went with 15mm shorter, 725 belt which is 5mm shorter than the original install at 730, all seems ok. All 3 belts I have used are from different compaines so don't know how precise their lengths were. So ya not an issue with the alternator, in fact a local service tech said he's never had to replace an aveo alternator