"Computer Nerd Kev" wrote in message
...
petrus bitbyter wrote:

This kind of failure is pretty common especially with coils and
transformers. In this components insulation tends to degrade partially
over
time, usually depending on the temperature. So a transformer may look
liko
te perform excellent while cold but fail when it grows warmer. Off
course,
other components may fail the same way sometimes. I'm afraid you to lack
both skills and equipment to find out what component(s) are actually
failing. Even well trianed and equipped professionals usually dislike
this
type of failures. And, you're right about the line output transformer.
Hardly a chance to find a good replacement.

OK, I'll pull the monitor unit out again to at least give the main board a
close visual inspection. Just my luck that the monitor is the only part of
the machine that I haven't got a schematic for.

Thank you for your help. It probably saved me a lot of messing about with
sync signals.


If its old, there might be issues with dried out electrolytic capacitors,
but these tend to improve as they warm up, but check whether there's a
coupling electrolytic between the horizontal driver transformer and the base
of the power transistor.

If the E/W correction starts to go awry at the start of the problem, the
fault may not be confined to the sync system - observe all the symptoms as a
whole and consider which part of the display unit as a whole could affect
all of them.