3. TROUBLE SHOOTING
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Only for training and service purposes
LGE Internal Use Only
3.18 USB Trouble shooting
The sequence of LGD690USB is,
USB connected to LGD690->VBUS_USB_IN(C89107) goes to 5V -> USB_D+ go to 3.3V -> USB_DATA is triggered
-> USB work
START
Check the Connection of
uUSB and Battery?
Check VBUS_USB_IN voltage
(4.7 ~ 5V, TP1 : C9107)?
Check +3V3_MTK_VUSB
(TP3 : C2336) is high ?
USB_D_P
(TP4 : FL9101) is high?
Check +4V9_VCHG_LDO voltage
(4.6 ~ 5V, TP2 : C9112)?
Change or charging the Battery
Change TA or uUSB cable
Check U4100(MT6323)
Check FL9101, uUSB cable
Check 94100(ChargerIC)
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Changed the main board