transmission on 1988 toyota camry

We got a really good deal from a friend on this 88 Camry earlier this year. I truly enjoy it. But we seem to have a recurring problem with what we believe is the voltage regulator. Took out the lternator and took it to an alternator shop. He says it bench tests fine. Talking to someon in service dept. at local dealer was informed voltage regulator is listed as separate part. Was the v. regulator an integral part of alternator on 88 Camry or mounted externally on this year of Camry. Where do I find it? Thanks for any help.