Usb Trouble Shooting - LG D405 Service Manual

3.19 USB Trouble Shooting

The sequence of LGD405 USB is, USB connected to LGD405 -> VBUS_USB_IN(C816) goes to 5V -> USB_D+ go to 3.3V ->
USB_DATA is triggered -> USB work USB Trouble shooting is shown below.
Battery voltage higher than 3.2V?
VBUS_USB_IN voltage
(4.7V~5V) TP1: C9402
Check +5V0_VREG_BHARGER is high?
Check VREG_L10_1V8 (TP3:C2359) and
(TP4:C2360) is high?
Change the Main PCB
LGE Internal Use Only
Start
Yes
Insert USB Cable
Yes
TP2 : C4142
Yes
VREG_20_3V075
Yes
USB_D_P is high?
(TP5:FL101)
Yes
No
Change or charging the Battery
No
Change TA or uUSB cable or Lower FPCB
No
Check U4100(PM8226)
No
Check U4100(PM8226)
No
Check Lower FPCB
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3. TROUBLE SHOOTING
Only for training and service purposes