Slide Key Backlight Led Trouble Shooting - LG KE590 Service Manual

4.20 Slide Key Backlight LED Trouble Shooting

z Slide backlight LED Operation scheme is shown below.
R100 R101 R102 R103
10 10 10
LD100 LD101 LD102
z Slide Backlight operation
- Slide backlight LED is controlled with LED_ABC signal
- LED_ABC signal from ABB(U102)
- The LEDs are forward biased and turned on
z Check Point
- VBAT level ( 3.35 ~4.2V)
- LEDs
Backlight will work properly
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Only for training and service purposes
VBAT
10
LD103
R104 0
START
Is the Voltage level VBAT
3.35 ~4.2?
YES
Are all LEDs LED100~103
(Slide key) Working?
YES
U103(Main) is
Working?
YES
4. TROUBLE SHOOTING
LED_ABC
NO
Charge Battery
NO
Check the soldering of each
R or Replace LESs not
working
NO
Check the condition
If problem, Replace U103(Main)
- 103 -
LGE Internal Use Only