LG KS20 - Smartphone 128 MB User Manual

LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
- 115 -
4.12 USB Troubleshooting
USB Initial sequence of KS20 is :
USB connected to KS20 power on → VBUS_5.0V(Q400) go to 5V → MSM7200 48M PLL work →
USB_DAT is triggered → USB_CTL_N go to 0V → USB work.
Start
C314 is 5V?
USB_CTL_N is 0V?
Check C314, CN300#16
Check U300 (pin 7)
NO
YES
YES
NO
Cable is inserted?
YES
Insert cable
NO
Power is on?
YES
Go to power on trouble shooting
NO
Check an U100 SMT status
by X-ray
Exchange U304 or
Change the Main board
And Retest

LG KS20 - Smartphone 128 MB Specifications

General

Brand	LG
Model	KS20 - Smartphone 128 MB
Category	Cell Phone
Language	English