I would look at the battery connections first, make sure the grounds are good ,often they get overlooked. and if you have a battery disconnect switch check that out too.
FOTON you were spot on. The Negative terminal and wire to it was corroded on the inside. Whenm trying to remove to clean it seperated from the terminal. Next day I
hooked jumper cables to connect the battery to the machine. The electric stuff came back on although I didnt try to crank the machne.