Recently, dealers have reported a two phase problem with the High-Res RGB
Monitor. To cure the jitter problem, they replace main logic board. Once the
board is replaced, they find themselves with a strange convergence problem.
None of the adjustments listed in Tech Procedures (including V-Twist, H-Stat)
cure the problem. Convergence can be as bad as 1/8" vertically. Adjusting the
V-twist control only brings in a small section of the screen leaving the top
and bottom borders way off. If the center section is adjusted correctly then
the picture gradually get worse towards the top and bottom borders where
distinct red, green (yellow), and blue shadowed images can be seen on the
screen.
The part that made this different than a normal convergence problem was the
fact that the shadowed images were all of different sizes. That is, green was
larger than the red, and blue was smaller than the red).
The solution is amazingly simple: Adjust the V-Top and V-Bottom controls on the
main logic board. This immediately brings the monitor into adjustment. No
parts replacements were necessary.
Interestingly enough, this board was supposedly received DOA from the Campbell
Support Center. It is possible that the apparent DOA condition was caused by a
dealer technician bumping these potentiometers when installing the replacement
board. It is also possible that these boards were not properly adjusted from
the factory.