Main Key Backlight Led Trouble Shooting - LG KE590 Service Manual

4.19 Main Key Backlight LED Trouble Shooting

z Keypad backlight LED Operation scheme is shown below.
VBAT
LED104, LED107, R126, R129 : NA
z Backlight operation
- Keypad backlight LED is controlled with MAIN_KEY_BL_EN signal
- MAIN_KEY_BL_EN signal from DBB(U102)
- The LEDs are forward biased and turned on
z Check Point
- VBAT level ( 3.35 ~4.2V)
- LEDs
- Q100(Main key)
- Main key, Main, Main FPCB connection
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Only for training and service purposes
MAIN_KEY_BL_EN
Q501
- 101 -
4. TROUBLE SHOOTING
LGE Internal Use Only