chassis 9-2143.pix drops down with retrace and pulls in on sides.gets worse if screen is turned up.tapping or violent shaking or freeze does not affect.swapped out yoke and fly with known good,str53041,numerous caps very intermittent,sometimes shutsdown.please any tips on this chassis even if seemingly unrelated to this problem.set came in for surge then dead,replaced B+ fuse and it played for a week with no problems. Mark Simpson Mark Electronics Plant City,FL (813)717-9700 Help make your TechAssist online repair tips database better! Submit your fixes here: http://www.circuitwork.com/techassist/tip/#tips To unsubscribe write to: techassist-request@xxxxxxxxxxxxx with unsubscribe in the subject line.