Rca p46721lv Problem

[SOPHM]

Just recently my RCA Rear projection started having the upper channels around 59 and up to about 73 would start having high pitch noise and the video would be sorta like a channel with no cable. I don't know really how to describe it.

When you go past 73 and you get a working channel and go backwards in channels they would work except a few but when you go forward there messed up again. Sometime it just works no problem. I took back off and tapped around but didn't help.

It ain't the cable provider cause no other TV does it.

Model P46721lV
Chassis PTL169PKA

Thanks.