I have a SuperVGA monitor that won't keep its focus. If I focus it when I first turn it on, it slowly goes out of focus as it warms up. If I try to keep it in focus as it warms up, I can keep it in focus, but some of the other adjustments peak out (like horizontal and vertical size) What is wrong with it?

This was a question posed on the Classic Computers mailing list. Whilst it is not specifically Amiga-related it may still be a problem for Amiga users who use an VGA or SVGA display such as those with a graphics card. I make no guarantee that this will work, it is just a suggestion on the problem.

It is possibly a high-voltage problem. In most monitors the focus supply (5kV or thereabouts) comes from
the flyback. As does the EHT to the CRT. And the EHT voltage does affect the size of the picture (higher EHT -> `stiffer' beam -> smaller picture for a given deflection field). Try to find the supply to the horizontal output stage, this is probably around 150V. Having a service manual helps. If that drifts as the monitor warms up, then debug the power supply. If it's steady, it is likely a problem with the divider network in the flyback. To find more information visit http://www.repairfaq.org/~filipg/ for additional help.

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