Mitsubishi Electronics DM Module Check, NetCommandTM Control Problems, CRT Phosphor Protection

DM Module Check

When the TV turns On, but a problem exists that may be caused by the DM Module, perform the following two checks:

1)Select the DTV Antenna as the source an select and HD Channel.

2)Select an analog 480i signal as the source and note if an On Screen Display (OSD) is present.

The ability to display Menus and receive an HD channel indicates the DMAssembly is functioning properly.

Except for the convergence crosshatch, all OSD signals are generated in the DM Module. When there is no OSD using a 480i source, the DM assembly may be the cause of the problem. However, before condemning the DM, make certain it is properly seated onto the PCB-DTV TUNER and that all connections between the PCB-DTV TUNER and PCB-SIGNAL are secure.

NetCommandTM Control Problems

If devices in a Home Theater System cannot be con- trolled properly with NetCommand, the Remote Con-

Error Code	Probable Cause
12	No error detected
21	X-Ray Protect
22	Short Protect
23	Loss of Deflection

Table 9-2: Error Codes

trol may not be in the NetCommand Operational Mode. To put the Remote in the NetCommand Mode:

1)Set the Remote to the TV Layer.

2)Point the Remote away from the TV.

3)Press and Hold the "POWER" button and enter "9-3-5" in sequence.

CRT Phosphor Protection

Troubleshooting problems in the CRT Protect, De- flection Loss Detection and the Deflection circuits, sometimes involves disabling the CRT Protect cir- cuitry and then Powering up the TV.

However, first disable the CRTs to prevent any possible phosphor damage.

1)Unplug the SP connector at the PCB- CRT(R). This removes the filament voltage to all three CRTs.

2)Remove zener diode D5A13 on PCB-MAIN. This disables the CRT Protect circuit.

The set then can be switched on for troubleshooting without damaging CRT phosphors.

9-2