3. TROUBLE SHOOTING
- 50 -
Copyright © 2014 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3. 14 USB
3. 14. 1 USB
The sequence of USB connection:
USB cable is plugged into L25 and host device USB_VCHG goes to 5V USB_IO_P goes to 3.05V USB_DATA is
triggered USB working
END
Start
Check connection of
u-USB and Battery
USB Connection OK?
C4144(
TP1
), C9203(
TP2
)
Is About 5V?
Check
+5V0_VREG_BHARGER (C4143)
TP3
Over 4.35V?
Is USB DM(
TP4
)/DP(
TP5
) Triggered?
Check
USB Connection
OK?
Change I/O Connector
Change TA or USB Cable
Check Q4100, Q4101
Check
PM8926 (U4100)
Check the FL9203
Change main BD.
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO