Keypad Backlight Trouble - LG MG200 Service Manual

4. TROUBLE SHOOTING

4.11 Keypad Backlight Trouble

Backlight Operation
• The keypad LED backlight is controlled with LEDB signal.
• LEDB signal from ABB.
• The LEDs are forward biased and turned on.
Trouble Shooting Setup
• Connect PIF-UNION to the phone, and power on.
• Enter the engineering mode.
• Go to menu "Baseband ¡ LED ¡ Backlight ¡ Keypad on"
Trouble Shooting Procedure
• Check the soldering of components
• Check the LEDB signal
• Check LEDs
Check Points
• LEDB signal
• LEDs
R316
LEDB
20
R318
20
VA306
LEDB
Check
soldering !
- 64 -
R316
20
R318
20
VA306
Check
LEDB signal
R316, R318
Check
soldering !
Check
LEDB signal
R316, R318