Mitsubishi WS-55809 video problem
 

Have a Mitsubshi WS-55809 projection TV with an odd video problem. The set has
a black screen on all inputs except RF, which gives a gray (grey?) screen. The
displays appear all black, indicating the blanking is getting through. Sound
works fine; I have composite video on rear monitor outputs. I don't have the
manual; has anyone seen this particular problem before?
TIA
Billy