Strong SRT8500 Service Manual page 15

2) Screen problem in color
If you have Black-and-White screen. It mainly results from distorted 24MHz
frequency. In case of no screen display or different
color displayed, it also mainly results from the Y401 problem. Additionally, in case
that the screen display works but is with one color only, for example blue, green,
or red, it mainly results from software fault(possiblely detected only on RGB TV).
RGB Circuit
RED GREEN
BLUE