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LGE Internal Use Only
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
5. Trouble shooting
GD910 service manual
5.4 USB Trouble
Checking
Checking
Cable is insert?
OVP_VUSB(C245) is
about to 5V?
Start
END
Cable insert
Check soldering or
change U203
NO
YES
YES
VDD_CHARGE(C202) is
about to 4.8V?
NO
YES
USB_VCHG(C242) is
about to 5V?
Change cable
NO
YES
Check soldering or
change D202
USB function is ok?
NO
Change U202 or
main board
Cable is insert?
Is OVP_VUSB(C446)
about 5V?
Check TP2
Start
END
Cable insert
Check soldering or
change U407
NO
YES
YES
Is VDD_CHARGE
about to 4.8V?
Check TP3
NO
YES
Is USB_VBUS(C447)
about 5V?
Check TP1
Change cable
NO
YES
Check soldering or
change D201
Is USB function ok?
NO
Change U201 or
main board
Cable is insert?
OVP_VUSB(C245) is
about to 5V?
Start
END
Cable insert
Check soldering or
change U203
NO
YES
YES
VDD_CHARGE(C202) is
about to 4.8V?
NO
YES
USB_VCHG(C242) is
about to 5V?
Change cable
NO
YES
Check soldering or
change D202
USB function is ok?
NO
Change U202 or
main board
Is Cable inserted?
Is OVP_VUSB(C303)
about 5V?
Check TP2
Start
END
Insert Cable
Check soldering or
change U300
NO
NO
YES
YES
Is VDD_CHARGE
about to 4.8V?
Check TP3
NO
YES
Is USB_VBUS(C304)
about 5V?
Check TP1
Change cable
NO
YES
Check soldering or
change D300
Is USB function ok?
NO
Change U200 or
main board
Checking Flow
Checking Flow
Checking Flow
Checking Flow
Checking
Flow