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LGE Internal Use Only
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
4.9 USB Troubleshooting
USB Initial sequence is :
USB connected to I/O connector
Æ
VBUS(C224) go to 5V
Æ
USB_DP go to 3.3V
Æ
USB_DN go to 400mV
Æ
USB work.
NO
YES
YES
NO
YES
NO
YES
NO
[ USB Troubleshooting Flow ]
Start
Change the main board
Connect USB cable
Go to Power on trouble shooting guide
Check the USB cable
Check the USB cable
Cable is connected ?
Power is ON ?
C224 is 5V ?
USB_DP is 3.3V ?