LG U300 Service Manual page 88

4.6.2 Checking Ant. SW Module
Refer to chapter 3.4
4.6.3 Checking RF Tx level
TP3
ANT100 ANT101 ANT102
SW100
C199
G2
ANT RF
G1
6.8p
KMS-512
C101
L104
0.75p
8.2nH
Test Point (RF Tx Level)
L101
7.5nH
TP1
C106
33p
23
GND6
22
ANT
21
GND5
20
TRX
U100
19
GND4
18
NC9
17
CXG1190AEQ
NC8
16
NC7
15
NC6
14
NC5
TP3
TP2
Schematic of RF Tx
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4. TROUBLE SHOOTING
TP2
TP1
1P7T SWITCH ANT_SEL0 ANT_SEL1
GSM 900 TX H
GSM 1800/1900 TX
H
GSM1800 RX
L
GSM1900 RX L
GSM 900 RX
L
UMTS RX/TX H
VREG_RFRX_0_2.85V
C102 C103
0.1u 10p
R101
ANT_SEL0
0 R102
ANT_SEL1
0 R103
ANT_SEL2
0
1
GND1
2
RX2
3
RX3
4
RX4
5
RX1
6
GND2
7
NC1
8
NC2
9
NC3
10
NC4
L121
9
DCS_PCS_OUT DCS_PCS_IN
C122 C123
4.7nH
1p 1p
BAND_SELECT
26
GND17
27
GND18 TX_ENABLE
28 U102
GND19
29
GND20
SMPY0008901
30
GND21
31
GND22
32
RF3166
GND23
L122
8
GSM_OUT
C138 C139
8.2nH
3.3p 3.3p
ANT_SEL2
H L
L L
H H
H L
L H
L H
R105 100
C113
15p
R108 100
C117
15p
1
2
3
4
VBATT
C132
5
GND 22u
6
VRAMP
7
GSM_IN
R125
0