
LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
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4.4 Checking VC-TCXO Block
The reference frequency (19.2MHz) from X100 (VC-TCXO) is used in UMTS TX part, GSM part and
BB part.
Schematic of the VC-TCXO Block
TCXO
R123
100ohm
0.01u
C175
0.1uF
C169
C172
100p
4
VCC
5
TC7SH04FU
U105
GND
3
2
0.01u
C171
1000p
C170
1000p
C173
NC1
5
6
NC2
NC3
7
8
NC4
3
OUTPUT
4
VCC
1
VCONT
DSA321SCE-19.2M
X100
19.2MHz
GND
2
R124
100K
C174
1000p
TRK_LO_ADJ
VREG_TCXO_2.85V
TCXO_BT
VREG_BT_2.85V
TCXO_PM
RTR6275_TCXO
TP3
TP1
TP2
X100
Test Point of the VC-TCXO Block
TP1
TP3
TP2
Summary of Contents for U370
Page 1: ...Date January 2008 Issue 1 0 Service Manual Model U370 Service Manual U370 ...
Page 178: ...Note ...
Page 179: ...Note ...