Philips 28PW9527

Has anyone any idea what can cause the problem with my Phiips 28" Pixel plus
TV?

I bought this just over a year ago and almost since new it has exhibited an
intermittent fault. Most days from time to time the picture will compress
from the bottom of the screen to arouund half height(ie a large black bar at
the bottom), it then rights itself after around 3 seconds. This will occur
irrespective of the input source.

Currently it is at the vendors for the third time, having been returned to
me twice without them being able to see the fault for themselves.


TJP