LG GB220 - Page 70

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Only for training and service purposes
LGE Internal Use Only
4. TROUBLE SHOOTING
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
(1) Checking Crystal Circuit
TEST POINT
CIRCUIT
WAVEFORM
CHECKING FLOW
Figure 4.3.1
26 MHzO.K?
No
Crystal is OK. See next page to
check PLL Circuit
Yes
Replace X100
Figure 4.3.2 Figure 4.3.3
X100
1 pin : 26MHz
2V85_VSIM
GND
4
1
TER1
2
TER2
XTAL
3
EXXY0026401
FA-20H
X100
26MHz
C125 0.1u
EOC
nLCD_RESET
UART_TX
UART_RX
USB_P
SIM_RST
SIM_CLK
SIM_DATA
USB_N
1 pin