4.8 USB Troubleshooting
USB Initial sequence of KF390 is :
USB connected to U370 power on
→
USB_VBUS(VA404) 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
at VA404
YES
Voltage of USB_D+ is 3.3V ?
YES
NO
Check I/O Connector
NO
Check PM6658
LGE Internal Use Only
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Only for training and service purposes
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Содержание KF390
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