Slide Key Backlight Led Trouble Shooting - LG KE500 Service Manual

4.20 Slide Key Backlight LED Trouble Shooting

z Slide backlight LED Operation scheme is shown below.
VBAT
R103 R104
10 10
LED100 LED101
R134
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
Are all LEDs LED100~101
Backlight will work properly
R103
0
LED_ABC
START
Is the Voltage level VBAT
3.35 ~4.2?
YES
(Slide key) Working?
YES
U103(Main) is
Working?
YES
- 103 -
4. TROUBLE SHOOTING
LED101
NO
Charge Battery
NO
Check the soldering of each
R or Replace LESs not
working
NO
Check the condition
If problem, Replace U103(Main)
R134
LED100
R103