SAMSUNG PS42Q7XEH
Service Manual

Troubleshooting

6-2 Checkpoints by Error Mode
6-2-1 No Power
Symptom - The LEDs on the front panel do not work when connecting the power cord. - The SMPS relay does not work when connecting the power cord. - The power of the unit seems to be out of order.

The SMPS relay or the LEDs on the front panel do not work when connecting the power cord if the cables are improperly connected or the Main Board or SMPS is out of order. In this case, check the following: - Check the internal cable connection status inside the unit. Major Checklist - Check the fuses of each part. - Check the output voltage of SMPS. - Replace the Main Board.

Troubleshooting Procedures

Are the AC IN socket connector and the Main SMPS CN800 connected? Yes

No

The AC IN socket connector and the Main SMPS CN800 connected

Is the Fuse (F801S) of the Main SMPS Power Input Part blown? Yes

No

Replace Fuse (F801S)

Main SMPS CN804-1 Pin 3 : STB 5V Pin 8 PS-ON : Check to see if it is 0V Yes

No Replace the Main SMPS

Replace the Main Board

6-2

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