Gramp - When I took it to a "diesel-electric" repair shop he said "Who the hell is Balmar? Never heard of them. I probably can't get parts - take it somewhere else!" Then I called the two largest boat repair shops in the area - both of them use that "Diesel-electric" shop! I called all of the alternator repair shops in the area, none of them had ever heard of Balmar!
Doesn't really give one a feeling of confidence! I called three auto repair shops, including the one I take my own cars to. They don't repair alternators; Auto alternators are cheap enough they throw them away and buy new ones! I guess I should take it apart and see if Radio Shack can supply similar diodes!