
4.10 USB Troubleshooting
USB Initial sequence of U370 is :
USB connected to U370 power on
→
USB_VBUS(Q300) go to 5V
→
USB_D+ go to 3.3V
→
USB_DAT is triggered
→
USB work.
Start
Power on was OK ?
YES
NO
Go to Power on Trouble shooting
Change the Main board
Insert the USB Cable, and
Check Voltage of USB_VBUS
pin of U304 is 5V ?
YES
Voltage of USB_D+ is 3.3V ?
YES
NO
Check I/O Connector
NO
Check PM6650
LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
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Summary of Contents for U370
Page 1: ...Date January 2008 Issue 1 0 Service Manual Model U370 Service Manual U370 ...
Page 178: ...Note ...
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