SECTION3 ELECTRICAL

ELECTRICAL TROUBLESHOOTING GUIDE

1. Power Circuit(SMPS)

(1) No 5.3 A

No 5.3V

NO

Is F101 normal?

Replace F101(Use a specified

(2) No 9V

No 12V

NO

YES

NO

Is BD101 normal?

YES

fuse).

Replace BD101.

Is D109 normal?

YES

Is Q170 normal?

YES

NO

Check/Replace D109

Replace Q170

Is R101 normal?

NO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

YES

 

 

 

 

 

 

 

 

Is there Vcc (about 13~19V) at

NO

IC101 pin 5?

 

 

 

Replace R101.

Is D103 normal?

NO

Check/

Replace D103

NO

Is D110 normal?

YES

NO

Is Q152 normal?

YES

Check/ Replace Q163

Replace D110

Replace Q152

YES

Is D106 normal?

YES

NO

Replace D106.

(3) No 24 V

Is there about 2.5V at

NO

IC103 pin 1?

 

 

 

 

 

 

 

YES

 

 

 

 

 

 

 

 

 

 

 

Replace IC103.

No 24V

NO

Is D109 normal?

NO

 

 

 

 

 

 

YES

 

 

 

NO

 

 

 

 

 

Is L103 normal?

 

 

 

 

 

 

 

 

 

 

YES

Replace D109.

Is L103 normal?

Is D110 normal?

YES

Is Q159 normal?

YES

NO

Check/Replace D110

Check/Replace Q152

Check the power terminal at main

PCB short.

Check ‘H’ signal at Q161

Base terminal

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LG Electronics TL-AT130M service manual Power CircuitSMPS No 5.3 a, No 24