On Dec 16, 9:35 am, "Michael Kennedy"
wrote:
I've had this Viewsonic PF790 19" CRT monitor for quite a few years now and
it has been used daily since it was new without any issues. Recently I have
noticed that large white images will cause the horizontal size to shrink
about 1cm overall.

start with the simplest: by changing the caps on the b+ line from the
power supply to the horizontal/line stage.. typically rated 160 volts
or more. don't bother measuring them, just replace. if no joy, then
work back into the primary of the power supply.

chances are this monitor has a few years of life left in it , so
don't give up and buy one of those 'orrid LCD things.

let us know how it goes.
-B.