Hello Friend. Check at the source. resistors, zener diodes and rectifiers, and change the small filters to new ones, and check or change the regulator and the opto coupler, then solve the choper and flay back pins, and then after the choper check diodes, resistors, and filters , and check the tsh. and the filters, and diodes that are right there in the horizontal stage, may be that the + b filter is undervalued. Cheers