LG KU730 Service Manual page 87

4. TROUBLE SHOOTING
4.6.5 Checking RF Rx Block
ESHS-L090UB FL100
7 1
GND1 EGSM_RX1
9 2
GND2 EGSM_RX2
11 3
GND3 DCS_RX1
13 4
GND4 DCS_RX2
18 5
GND5 PCS_RX1
20 6
GND6 PCS_RX2
17 8
VC1 DCS_PCS_TX
15 10
VC2 EGSM_TX
14 19
VC3 UMTS_TX_RX
NA
R106
NA
2.2K
C121
68p
C125
C126
33p
22p
NA
NA
TP1
TP
TP2 TP
TP3
TP
Test Point (RF Rx Block)
TP2: DCS Rx
GSM_PA_RAMP
TP3: GSM Rx
C127 22n
+VPWR
C137 C129
100u
0.01u
Schematic of GSM/DCS/PCS Rx Block
TP1: PCS RX
VREG_SYNTH_2.85V
L110 4.7nH
L112
8.2nH
1805-1880 MHz
L114
C117
NA
NA
L115
8.2nH
L118 4.7nH
L120 12nH
L121
22nH
925-960 MHz
L122
C128
NA
1000p
L124
22nH
L126 12nH
- 88 -
L104 4.7nH
1930-1990 MHz L106
56nH
L108 4.7nH
VREG_RFTX_2.85V
C108
C107
0.1u 33p
R103 R104
4.7K 4.3K
0.01u
C115
C109
6.8n
680p
C112
(PPS)
C118
0.1u CP_HOLD2
29
CP2_OUT CP2
30
VDDA9
31
RX_VCO_IN
RX_VCO_IN
R107 32
R_BIAS
11.3K (1%) 33
GSM1800_INN
34
GSM1800_INP
35
VDDA10
36
GSM900_INP
37
GSM900_INN
38
(1%) (1%)
VDDA11
R110 100 R111 0 39
TX_MOD_CP
40
VDDA12
(1%) 41
C130 C131 TX_VCO_FB
R114 33
42
120p 330p
C134 5.6n C138
82p
(PPS)
C1
33
RTR625
U100