Key Backlight Led Trouble - LG C1100 Service Manual

4.10 Key Backlight LED Trouble

Test Points
Figure 4-22.
Checking Flow
START
Is the voltage
level VBAT
3.6-4.2V?
Are all LEDs
LD111~LD120t
working?
BACKLIGHT WILL
WORK PROPERLY.
LIGHT3
port of
ABB
Light3
No
Yes
No
Yes
Circuit Diagram
To
VBAT
R111 R112 R113 R114
47 47 47 47
LD111 LD112 LD113 LD114
SP102 SP103 SP104 SP105
Check the U102.
Check the soldering of each R or replace LEDs not working.
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4. Trouble Shooting
R115 R116 R117 R118 R119
47 47 47 47 47
LD115 LD116 LD117 LD118 LD119
SP106 SP107 SP108 SP109 SP110
R120
47
LD120
SP111