Usb Trouble - LG E900 Service Manual

4.12 USB trouble

USB Initial sequence of LG-E900 is :
USB connected to LG-E900
MUIC operation (IC400)
Start
Cable is insert?
YES
VCHG_VBUS is about
to 5V? (TP1)
YES
USB DATA line any signal?
(TP2)
YES
Change the Main board
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Only for training and service purposes
VCHG_VBUS(FL400) go to 5V
USB work
NO
Cable insert
NO
Check FL400
NO
Check IC400 (TP3)
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4. TROUBLE SHOOTING
LGE Internal Use Only