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LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
- 66 -
4.2 Checking VCXO Block
The reference frequency (19.2MHz) from X100 (TCXO) is used in UMTS TX part, GSM part
and BB part.
Check 1. Crystal part
If you already check this crystal part, you can skip check 1.
Schematic of the Crystal Part
Test Point (Crystal Part)
TCXO
0.01u
C137
C147
1000p
C144
1000p
C140
1000p
R124
100K
C134
0.01u
1u
C130
GND
3
2
4
VCC
5
2
OUT
3
4
VCC
1
VCONT
TC7S04FU
U104
TG-5010LH_19_2M
X100
19.2MHz
GND
R118
100ohm
0.1u
C129
C145
RFR6275_TCXO
TRK_LO_ADJ
TCXO_BT
VREG_BT_2.85V
TCXO_PM
RTR6275_TCXO
VREG_TCXO_2.85V
1000p
TP1
TP2
TP3
TP4
TP1
TP2
TP4
TP3
Summary of Contents for CU405
Page 1: ...Date May 2007 Issue 1 0 Service Manual Model CU405 Service Manual CU405 Internal Use Only ...
Page 175: ...Note ...
Page 176: ...Note ...