My ten-year old Mitsubishi 36" plays fine thru cable box but no longer plays DVDs. I get a scrambled picture and no audio. I hooked up DVD player to another TV and it works fine, so problem is not with DVD player (JVC). Then I tried straight connection between TV and DVD player. TV goes into automatic channel search and doesn't stop until I reconnect it to cable box. Does anyone know if this will involve a costly repair or is there a simple fix that I can do?