LG CU920 - Page 102

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4. TROUBLE SHOOTING
4.8.3 Checking Rx Block
1. TP1 : GSM850 Rx Balance Input
2. TP2 : GSM900 Rx Balance Input
3. TP3 : PCS Rx Balance Input
4. TP4 : DCS Rx Balance Input
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Only for training and service purposes
TP1 TP2 TP4 TP3
Fig. 4.8.3.1 Test point of the GSM RX Block
56nH
C102
47nH
L120
L119
18nH
L118
22nH
L116
27nH
NA
L101
L100
4.7nH
3.3nH
L110
L108
18nH
L113
NA
2.7nH
L107
L111
27nH
L114
68nH
56pC100
L102
NA
NC
15
UMTS1
UMTS2
16
14
VC1
VC2
13
12
VC3
VC4
11
10
VDD
21
GND5
23
GND6
24
26
GND7
27
GND8
GND9
28
GSM1800RX1
1
2
GSM1800RX2
GSM1800_1900TX
22
GSM1900RX1
3
4
GSM1900RX2
7
GSM850RX1
GSM850RX2
8
25
GSM850_900TX
GSM900RX1
5
6
GSM900RX2
17
LMSP4LMA-573TEMP
FL100
19
ANT
GND1
9
GND2
18
20
GND3
GND4
22nH
L121
L106
3.3nH
4.7nH
L104
Fig. 4.8.3.2 Schematic of the GSM RX Block
TP3
TP1
TP2
TP4