LG LG9200 Service Manual page 58

Keypad Backlight Trouble (Number Key) : (3)
1. All LEDs are not working
START
Enter into Engineering Mode
and select Keypad On
CN301,CN901,FPBC is o k?
No
The Volta ge of LE DB or
SOFTKEY_LED signa l
is about 0 V?
Power off and Measure the
Yes
Resistor Value of all LEDs.
Is t here an yt hing that
resist or valu e acro ss L ED
is unde r 10 ?
No
Keypad D ispla y i s OK.
2. Any LED is not working
START
Enter into Engineering Mode
and select Keypad On
The path is OK?
Yes
The LED is out of ord er.
Change the LED.
No
Re-solder CN301, CN901.
Reco nnect FPCB
ABB is out of orde r.
No
Change the Bo ard .
Replace t he LED.
Yes
It is out of or der.
Re-solde r the path
No
of LE D and Re sistor .
- 59 -
4. TROUBLE SHOOTING