Touch Screen Trouble - LG KC910 Service Manual

4. TROUBLE SHOOTING

4.16 Touch Screen trouble

Touch Initial sequence of KC910 is :
TOUCH_VDD_2.8V(C702) goes to 2.8V → TOUCH_PENIRQ_N(R723),TOUCH_I2C_SCL(R720) &
TOUCH_I2C_SDA(R721) go to high
Touch operation of KC910 is :
A finger is touching on the screen → TOUCH_PENIRQ_N is low → I2C is connected → A finger is
took off from the Screen → TOUCH_PENIRQ_N is high → I2C is not connected.
Touchpad Cal ibration
Conne cto r Is insert?
Replace t he Folder
Replace t he Main board
U703
C702 (TOUCH_VDD_2.8V)
R702 (TOUCH_PENIRQ_N)
R721(TOUCH_I2C_SDA)
LGE Internal Use Only
Start
Yes
Work w ell?
No
NO
YES
Yes
Work w ell?
No
- 172 -
End
Inser t Connector, again
End
Touch Window Connector
R720
(TOUCH_I2C_SCL)
Copyright © 2007 LG Electronics. Inc. All right reserved.
Main FPCB Connector
Only for training and service purposes