The diode trio and the built in regulator in the alternator would probably be a good start, the main fuse, what ever it is for that model of tractor, My Kioti is an inline 60 amp. Workshop manual is gonna be a must.. You need a good schematic, and and good multimeter, and know how to use both. Good luck.
James K0UA
Ahhh crap....a new alternator is $260,