Try the fuse pulling like a previous post said and next I would change the regulator/brush pack just to eliminate it as a problem source since it does cut the rotor current off and on to regulate electrical input to the whole system....Easy to change ....2 screws on the rear plate of the Alt....unhook battery first...

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1978 Yellow 300D (The Mustard Toad)
1980 Blue 240D (The Iron Toad)
1989 Grey Mitsu.4WD Mighty Max Pickup (Needs a Diesel transplant bad)

(Open the pod bay doors HAL)