Dear chemelec, spec and pfofit,
again thanks for the big help,
the black varistor indeed was a housing box for the original varistor,
this is the original faulty varistor:
View attachment 99144
the original one is look same as the replacement.
i guess the is no polarity for this part , because i dont see any sign for a polarity (e.g. +/-)
i opened the black housing box,
took out the faulty varistor,
put a new one inside the black housing box,
solder the fixed one to the circuit,
put a new fuse,
and today im gonna go back, up my roof to put the circuit back in.
and prey that no more parts got faulty on this circuit board.
i will update,
thanks .
itai.