Philips 15c Bad Focus after warmup

[Sugrue Family]

I have a Philips 15c monitor that has OK focus when cold, but after a while
is goes really fuzzy.
Have resoldered components on neck PCB ( This has helped on another
monitor ) but no improvement.
Any ideas / experience out there?

Thanks

 

[John Gill]

I would put a high-voltage probe on the focus pin and watch the focus voltage
as the set warms up. You can use a small diameter wire to wrap the pin with
so that you can put the CRT socket back on. The focus pin is the one within
the plastic "key" on the picture tube.
If the voltage drifts lower as the set warms up, you probably have a defective
focus pot on the flyback. I have heard of drilling a small hole above the
focus control on the flyback and squirting in some contact cleaner.
I have never tried this, but would consider it as a last resort before
replacing the flyback transformer.
Hope this helps....
John


"Sugrue Family" <gsugrue@xtra.co.nz> wrote in message news:<9qH1b.124650$JA5.2890519@news.xtra.co.nz>...

I have a Philips 15c monitor that has OK focus when cold, but after a while
is goes really fuzzy.
Have resoldered components on neck PCB ( This has helped on another
monitor ) but no improvement.
Any ideas / experience out there?

Thanks