The TS-830S used a 6 amp fuse for 115 volts.... I owned one once and it was
one of the finest transceivers I ever had.

IIRC neutralization was only really a big issue on the high bands like 10
meters anyway.... where you should see about 80 watts output.

I never had a 6140B final tube fail.... only a weak 12BY7A driver.... try
changing that one first if rated power is low.

Mike, W9WIS