LG GT500 - Page 116

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Only for training and service purposes
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4. TROUBLE SHOOTING
TP2
4.13.2
GPS
Clock
path
start
2. Check Buffered MCLKSEC
TP2: 26MHz
3. Check
MCLKSEC
TP3: 26MHz
1
2
TP4
(4
th
pin from the end
of the connector)
2
Go to 4.11.3
No
Yes
Replace U750
OK
NG
4. Check
Mainboard Connector
TP4: 26MHz
Replace Sub
PCB
OK
NG
Check RF3300
(U111)
Main PCB (Bottom side)
TP1
Sub PCB
TP3
1. Check TCXO output
TP1: 16.369MHz
1
Replace X750
No
Yes
4.13.2 GPS Clock path
NTIN
F5
C
CLK
_
PPS
E7
T
CXO
A2 F2
VDDE_1V8
X750
1
GND1
GND2
3
NC1
25
NC2
OUT
4
VCC
6
KT2520F16369ACW18T
C751
0.1u2.2u
C750
R757
0
GPS Clock Buffer
R754 100K
0.1u
C753
R752
10
33
R753
C754
2.2u
VDDE_1V8
A
GND
OE VCC
Y
NL17SZ126XV5T2G
U750
MCLKSEC
GPS_CNTIN
ACC_GP_GPS_PON
TP1
TP2
TP3
G3 G4
30 31
32
33
34
35
36
37
24
25
26
27
28
29
FM_ANT
MCLKSEC
RTCCLK
TP4