Make sure the connector on the remote board is good and secure.
(do this with the monitor OFF)
Turn the brightness and contrast on the remote board all the way down.
Now with the video input unplugged from the chassis...... ie no picture.
Adjust the SCREEN up until the screen is bright, then turn it down until it just goes to a nice black.
Plug the video input back in.
Adjust the brightness and contrast up a little at a time as needed.
Do any of those potentiometers NOT do anything ?
Do you happen to have a closer pic of your flyback ?
It may just be the way I see it in your other pics, but the SCREEN pot on the flyback doesn't look right /broke. (I'm just curious)
You may also try turning the red drive and cutoff down on the neckboard.
I know you mentioned adjusting colors already, but sometimes you have to backtrack and readjust things as you go.