Lcd Led Trouble - LG GX500 Service Manual

GX500 Operational Description

4.11 LCD LED trouble

Check Points
-Signal path is connected well
MLED
VA203
VBAT
C253
1u
Figure 4-27. LCD BACKLIGHT LED DRIVER Circuit
Checking Flow
START
Check All of LEDs solder
Check TP1 is
hlgh ?
Yes
Check TP2 is
high?
Yes
Assemble
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TP2
LCD BACKLIGHT LED DRIVER
TP2
C255
C254 1u
1u
EVLC18S02015
1u C 252
LCD_PWM
VA205
No
Check R224 and
No
Check and Replace
charge pump.
93/143
U205 AAT3369IDT-1-T1
1
OUTCP1
18 19
OUTCP2 EP
5
2 NC
C1-
3 15
C1+ D6
14
D5
4 13
C2- D4
17 12
C2+ D3
11
TP1
D2
6 10
IN D1
7 16
GND EN_SET
8 9
PWM FCAP
R224
C256
47n
10K
Replace
(U205)
- 9 -
4. TROUBLE SHOOTING
Revision A
MLED6
MLED5
MLED4
MLED3
MLED2
MLED1
LCD_BL_CTRL
TP1
LGE Internal Use Only
LGE Property