Once you learn enough, we need a lab quality monitor testers in a little box that outputs timings that is standard in use according to the VESA specs timing waveforms and IBM MDA, CGA, EGA, VGA, VESA timings not what you get with video cards so we can calibrate the monitors under repair correctly so it will work right with any video cards. And at *correct* voltage output so we can adjust the pots etc like you do following the service manuals.
And gray scale only from black, barely grey to white in 16 steps. Color not needed. Once you calibrate a monitor or tv correctly, you only need to set the wave forms to correct voltage, then adjust the grayscale on all the RGB colors to all white neutral with the brightest white, not too bright, actually comes out perfect for color when in use.
I had a monitor tester when bought along with tools to start my work, for my former work (repairing monitors and tv) and it was not correct timing vs video card that I knew well so I calibrated monitors using a Matrox G400! (concerning the resetting default centering and width, height etc).
Cheers,
Great Northern aka Canada.