Probably something in the bias circuitry to the CRT or in the video
processing circuitry. Could you post the diagnostics you may have actually
preformed and their results?
"ew123" wrote in message
oups.com...
I recently obtained an Philips 20PT1553-00 TV set. The picture is
usually relatively dark. I have to turn the brightness and the contrast
fully up to obtain a viewable picture. The effect of the
brightness-control is nearly non-existent. Sometimes (very seldom) the
whole picture brightens up and the brightness-control works. This lasts
usually bwetween 5 and 30 seconds. After that, the picture turns dark
again.

Has anybody experienced something like this before? Does anybody know
what could be wrong?

Thanks

Eberhard