LG M6100 Service Manual - Page 88

Key Backlight LED Trouble

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4. TROUBLE SHOOTING 4.11 Key Backlight LED Trouble TEST POINT CIRCUIT VBAT 47 47 47 47 47 47 47 47 C311 1u C312 1u C313 1u C314 1u C315 1u C316 1u C317 1u C318 1u R351 R350 R349 R348 R347 R346 R345 R344 LD308 LD307 LD306 LD305 LD304 LD303 LD302 LD301 Figure 4-11 Checking Flow KEY_BACKLIGHT R357 12K R358 12K 3 Q301 2 C319 1 2SC5585 27p R359 10 R360 10 LEBB-S14H X 8EA KEY_BACKLIGHT (WHITE LED) Main PCB START Is the voltage level VBAT 3.6-4.2V? Yes Are all LEDs LD301~LD308 working? Yes Q301 is working? Yes BACKLIGHT WILL WORK PROPERLY. No Charge battery No Check the soldering of each R or replace LEDs not working. No Check the condition of Q302. If problem, Change Q301 - 89 -

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4. TROUBLE SHOOTING
- 89 -
4.11 Key Backlight LED Trouble
KEY_BACKLIGHT
(WHITE LED)
X 8EA
LD307
R347
47
R359
10
R344
47
LD303
LD304
LD308
C312
1u
R358
12K
47
R348
LD301
LEBB-S14H
47
R351
C315
R346
47
1u
1u
C314
1u
C317
C316
1u
LD306
LD305
47
R350
R349
47
12K
R357
27p
C319
47
R345
1u
C318
1u
C311
C313
1u
VBAT
2
3
1
2SC5585
Q301
R360
10
LD302
KEY_BACKLIGHT
BACKLIGHT WILL
WORK PROPERLY.
START
Is the voltage level VBAT
3.6-4.2V?
No
Are all LEDs LD301~LD308
working?
No
Check the soldering of each R or replace LEDs not working.
Yes
Charge battery
No
Check the condition of Q302. If problem, Change Q301
Yes
Q301 is working?
Yes
TEST POINT
Checking Flow
CIRCUIT
Figure 4-11
Main PCB