First post, by aitotat
I have this 17" Orion 7E750BT9 that has too dim picture just like most old CRTs. But this one does not have G2 adjustment on the flyback transformer.
I found schematics only for some closely related model, 7A750 and those look very similar. Schematics show that there should be some kind of G2 adjustment, likely from service menu. I managed quite quickly to discover how to enter service menu: when power is off, hold down MENU and SELECT buttons when pressing power button. There won't be any picture until releasing MENU and SELECT but once they are released, picture appears and when entering menu, there are more controls than usual.
And it also has G2 ADJUST in there! Unfortunately it did not work. It cannot be changed. Since nothing else helped, I selected EI (EEPROM initialize) and that was a wrong move. It did change it, from 61 to 48 so to wrong direction. In the process all colors need to be re calibrated since those were reset just like everything else. But I still can't change the G2 voltage.
This is one of the cheaper monitors but looks nice and has sharp picture (after focus adjustments from flyback) and no noticeable geometry errors.
Any idea why G2 cannot be adjusted when it is in the service menu? Maybe the monitor needs some factory test bench signal or something?
But if service menu won't work, then maybe modify the G2_ADJ signal with resistors? I'm not expert at this and I don't fully understand how the adjustment works but in the schematics near flyback there are R916 then there are R911/R922 and R914. I would start by modifying one of those a little? Am I on the right track?