LG U830 KU830 Service Manual page 102

4. TROUBLE SHOOTING
More tips for not powering-on cases !
Main board failure:
1. Check short of +VPWR(4.2V) and GND ! → Change a board
2. Check short of L601/L602 and GND → If YES, PM6650 internal FET short ! → Change PM6650 or
a board.
3. Check if D701(diode), C704(33uF tantalum) and GND are short !
4. Check if LCD LDO output voltage is OK ! (C317) → Change LDO.
5. Check if LCD module is OK ! → Change LCD module.
L602 : VREG_MSME 1.8V
L601 : VREG_MSMC 1.375V
D701
C704
C317 : VREG LCD 2.8V
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