Samsung LHU30BS, 305TPLUS service manual Troubleshooting, No Power Smps

4 Troubleshooting

4 Troubleshooting

Notes: 1. Before troubleshooting, setup the PC ’ s display as below.

•Resolution: 2560 x 1600

•H-frequency: 98.7 kHz

•V-frequency: 60 Hz

2.If no picture appears, make sure the power cord is correctly connected.

3.Check the following circuits.

•No raster appears: Function PBA, Main PBA, Inverter, Panel

•5V develop but no screen: Main PBA

•+24V, +18V does not develop: SMPS, Main PBA

4-1 No Power (SMPS)

Plug in the Power Cable

Stand by LED On?

Yes

No

No

Check related circuit with IC801S 1 Vcc and Drain-Source Waveform (DSW) 2

3Aroind 20V at 2pin on

Yes

Check the Vcc Circuit from DS803

4Check DSW at ICM801S

Yes

Around 380V on CP803

Yes

Replace LCD Panel.

No

No

Change ICM801S and check the

related circuit

Check the related circuit whit ICP 801S

and QP801S

Check 24V output related circuit with

zener diode (DZM854)

Check IC 8008 DC/DC convertor for

5.4V output

Check ICM853(379Roo) for 18V output

4-1