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4. TROUBLE SHOOTING
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Copyright © 2011 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
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RF Switching control Logic is as below table.
Table 5 RF path switching control logic
Also we need a checking of FEM power supply pin whether the FEM operates well or not.
FIG 10 FEM Power schematic
Also we need a checking of FEM power input pin whether the FEM operates well or not.
Table 6 Recommended FEM supply voltage
W900
AWS
W2100
TP1 TP2 TP3 TP4
{wG\G
DNI
L204
K0
02
72
1
R
8p
C242
20
6L
F
12
02
91
12
81
01
16
13
8
9
7
6
11
5
4
14
3
15
2
1
17
UMTS1
UMTS3
GSM1800/1900RX1
ANT
GSM1800/1900RX2
GND1
GND2
GSM850RX1
3
C
V
2
X
R0
58
M
S
G
1
XT
00
91/
00
81
M
S
G
1
C
V
XT
00
9/
05
8
M
S
G
VDD
GND3
2
C
V
4
D
N
G
VC4
2
ST
M
U
5
D
N
G
D
N
G
P
p0
81
81
2
C
56p
C232
1.8n
L210
SW201
G1
ANT
G2
DNI
L211
56p
C233
8p
C243
7.5n
L205
1K
R206
DNI
C221
DNI
C220
p0
01
71
2
C
SW200
4
2
1
3
1
G
A
C
2
G
33p
C231
15n
L203
1K
R207
+2.85V_VDD_RF_SW
100n
L202
4.7K
R129
+2.85V_MDM_SDCC1
1u
C230
K7.
4
62
1
R
1K
R208
1K
R209
39p
C900
DNI
C239
39p
C901
120K
R128
ANT_SEL0
ANT_SEL1
ANT_SEL2
RX_PCS_DCS_M
TRX_W2100
RX_PCS_DCS_P
TRX_W900
RX_G850_M
RX_G850_P
ANT_SEL3
MS_DET
TRX_AWS
4.7kohm
TP6
TP5