Help needed

I have a problem when I use the RGB output to my Panasonic 32PF TV - the picture flickers at the top of the screen.I know there are other posts which suggest getting into the service menu & making adjustments to the DVCO -I have done this but the flicker is stilll there.To make matters worse when I use S Video the picture starts wavering in the background which is more noticeable on Region 1 discs.
It is doing my head in - anybody had similar problems or any ideas on how to fix it.The s Video problem has occurred on all my DVD players to date.
Any help would be appreciated.