Alternator question.

[cmyc5575]

I replaced the alternator in my 82 today bc when i went home last night about half way down the high way all the lights started to dim and eventually shut off then seat belt light and buzzard went off. The new alternator is working good I checked all the wires and the look fine. My question that I have tho is when i took the old alternator to the auto store to get my core charge back they tested it and stated that it passed all their tests but the bearings were shot in it, so if this is the case could the bad bearings cause alternator to not charge the battery? Thanks for the input and advice.