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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4.8.2 UMS(USB MASS STORAGE) trouble
UMS Initial sequence of KC910 is :
USB connected to KC910
→
VREG_5V(C501, UMS) go to 5V
→
VREG_USB_3.3V(C515) go to 3.3V
→
USB_DATA is triggered
→
USB work
Start
VREG_5V is about
to 5 V?
VREG_USB_3.3V is
about to 3.3V?
MICRO SD function OK?
Chang e th e Main bo ard
Check C501
Check C302, C515, USB CA BLE
Follo w th e micro sd troubl e
NO
YES
YES
YES
NO
NO
Cabl e is insert?
YES
Cable inser t
NO
C515 (VREG_USB_3.3V)
C501(VREG_5V)
C302(VREG_USB_3.3V)