Monitor – colors level

Hi,
I have two bad monitors. One with CRT tube broken and other with final transistors broken.
The monitors are: IBM, model 6547, types G74, 19 inches, OSD.
I made one from these two bad monitors.
All is OK except the colors (a green dominant).Inside the monitor I can’t find any point of regulation .
Know somebody how I can turn on “service mode” or other methodology to change the level of the colors (except from VGA card)?