nanao ms 29a

got a Nanao MS9-29A that the Green Gain does not work for some reason (no change even with full rotation to stops of G-GAIN pot) Green cut off on chassis works fine Green gain seems to be stuck a little above center position and tends to bleed through a little Note the following has been done...

Good evening , Can I ask anyone familiar with nanao ms 29 monitor (got this from a versus city) this monitor sort of works (image in screen does not occupy the full width of the crt screen, another issue I need help with, cant seem to find ha "horizontal width" potentiometer of some sorts) ...