bad pulley?

my roommate has a 98 protege... it keeps snapping alternator belts... i hear this is a common problem. any input will be appreciated... it seems like the bearings are fine and everythign is lined up properly... wtf do i do?

im not a mazda guy at all... give me my bulky gm nonsense, lol

Same problem with my daughters '99 1.8 and wifes '01 2.0 Protege. Other than making sure the belts are lined up which you've done and making sure the grooves in all the pulleys are clean and not worn you've got one other thing. Make sure the belts are good ones, may cost a bit more but it does make a difference. It's a fine line between too tight and not tight enough...Mike