Toyota Repair: 1991 Camry Alternator Fuse problem, positive cable, battery cable

Question
QUESTION: My mother-in-laws 1991 Camry wouldn't start one day so I was called into the rescue. I check the usual problems and have narrowed it down to the alternator fuse. I replaced it and it blew immediately. I replaced another after disconnecting the alternator itself and it blew again. Any ideas on what's causing it to short out? What steps can I take to narrow down the problem?

Any suggestions would be greatly appreciated.

ANSWER: There are two alternator fuses, is it the 7.5 amp or the larger 80 amp?

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QUESTION: It's the larger 80 amp coming off the positive battery cable.

Answer
Disconnect the positive cable from the starter, be sure it does not touch any metal parts, disconnect the battery first then the starter connector and insulate it, then reconnect the battery and see if the fuse stops blowing, what I'm getting at is that I believe that the starter may be shorted internally.