Monitor Color Problem
Whenever there is a problem about missing color, the first thing i do was to gently tap the Cathode ray tube (CRT) board with a screw driver. Many times it was only dry joints that cause missing colors. Next i would check the VGA connector pins to see if there are any bend in it. Don’t be surprise that it happens many time where i found one of the pins that relate to colors bent. Pin 1 is for red, pin 2-green and pin 3 is blue. If one of these pins bend, it will cause a missing color in Monitor.
If the above procedure found no problem, i will direct replace the video pre-amplifier and then the CRT color driver IC. If the problem still exist, i will use oscilloscope to troubleshoot it. Color section problem is very easy to repair because it consist of three similar circuit. Even if one of the color section components burnt, i can easily get the same value back by comparing with the other two color circuits. A missing Monitor color problem rarely caused by a defective picture tube but somehow sometime i would still use a CRT rejuvenator to really confirm that it is in good condition before i start repairing it.