LGE Internal Use Only
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4.9 USB trouble
USB Initial sequence of CT815 is :
USB connected to CT815
→
VCHG_VBUS(R409) go to 5V
→
USBH_SEL go to 0V(U404
Pin#10)
→
USBH_CS go to 1.8V (R403)
→
USBH_DM go to 3.3V (U404 Pin#7)
→
USB_DATA is triggered
→
USB work
4. TROUBLE SHOOTING
- 108 -
Start
VCHG_VBUS i s about
to 5 V?
USBH_DM is about to 3.3V?
Change the Main board
Check Z D401, U402,
FL401,R409
USB c able
Check U404
NO
YES
YES
NO
Cabl e is insert?
YES
Cable in sert
NO
USB_DATA(0) i s about to 1.8V?
YES
NO
Check U403
Summary of Contents for CT815
Page 1: ...Date May 2009 Issue 1 0 Service Manual Model CT815 Service Manual CT815 Internal Use Only ...
Page 221: ...Note ...
Page 222: ...Note ...