Hi folks,
I have never encountered this problem,
My system
Sony 7700 multi reg (paragon)
Qed Squart cable
Panny 32PK20
Although As soon As I got the TV (grey import) I turned of the AI (nasty artifacting on dark colours during fast motion)
and Ive never encountered any Bars.
Suggestions (Ive only proof read the above posts)
1. Magnetic interference (speakers sub - nonshielded cables etc)
2. AI (enough said)
3. RF interference (cables etc)
Hope this helps Ill fiddle about with my set to try & recreate your problems and then get back to ya
Good luck