The focus voltage or the high voltage is changing. You will have to use an
HV probe to verify this. It is very possible that the HV multiplier is
defective, or a component(s) in the HV feedback for the HV regulation is
failing. Obviously the fault is thermo sensitive, by the way I interpret
your description.

--

Jerry G.
=====


"jmuller" wrote in message
...

I have an old (1997) SVGA computer monitor (labled FIG S567) which gets
blurry once it's warmed up. I feel the tube is still good because when cold
the picture is reasonably sharp.

It used to get blurry AND brighten up when it was warm. However I
re-soldered the flyback transformer and adjusted the 'SCREEN' voltage. It
does not appear to brighten anymore.

I am hoping this is a fixable problem, and am having trouble determining
just where the problem lies.

- jmuller.