musical fidelity a3.2 blown left channel, repair?

The voice coils probably overheated and started chaffing and eventually arced to ground this probably overheated and blew the output transistor(s) in one channel on your amp. You should get the amp repaired - the speakers will need new drivers but you might as well get new speakers as it won't be worth the cost to repair them.

MF's repair is in Charlotte, NC last I heard. I know the person doing it and he has been in audio about 30 years and is very competent.

You know your roomies ( and their friends) -if you think they blew 'em - they should be up for the cost of repairs.
Disconnect amp from power and speakers - remove covers - if you know what a fuse looks like -look for a blown one in one channel- these can be a anywhere - but back panel,top of PC board or bottom of PCB are most likely locations.Most stereo amps are symmetrical - look at the working channel and then look at what is different about the non-working channel -anything scorched/burned or bulged in the dead channel that looks better in the working channel is suspect.If you ( or the roomies) have led exemplary lives - maybe it'll be a fuse?
Don't assume the speaker is blown until you've had it tested.

well, i already got a pair of nht classic 3s to replace the old B&Ws (got a great deal here on audiogon). it was a good excuse to upgrade and, believe me, i'm keeping the hi-fi equipment out of the common space from now on. and thankfully i have a rega brio 3 that will get me by until i repair the MF.

thanks for the comments/suggestions. i do know what a fuse looks like, but i'd rather have a professional take a look. the roommates have agreed to pony up for any potential repairs/replacements.