Mits WS-55711 Black Screen / Tuner lock-up

Has anyone seen a problem with the Mits WS-55711 projection TV with the Tuner locking up with a Black Screen ?? The main tuner on the TV is frozen, cannot change channels but Sound Works. Some of the other inputs intermittently work (Inputs 1-4). If it works, later the picture will go blank and the net command also will not re-appear, you must move through the prompts with no video to get back to the working inputs. We are using the TV with a HD Tivo connected to the HD inputs (works great all the time) We also can watch our cable box on the the YprPb High Res. Inputs with no problems. The problem is the Main Tuner and the low-resolution inputs. Tried the normal reset and unplugging for a while. Tried all hard resets with no luck? Any other suggestions ?? I have a electronics backgroundÂ…