LG U830 KU830 Service Manual page 95

4. TROUBLE SHOOTING
4.6.5 Checking RF Rx Block
EGSM RX
PCS RX
DCS RX
U500
19 7
VDD GSM850_RX1
8
GSM850_RX2
18 5
CTRL1 GSM900_RX1
22 6
CTRL2 GSM900_RX2
1
GSM1800_RX1
2
GSM1800_RX2
10 3
GND1 GSM1900_RX1
12 4
GND2 GSM1900_RX2
13 9
GND3 WCDMA2100
15
GND4
17
GND5 DGM085M01
20
GND6
21 16
GND7 GSM850900_TX
23 14
GND8 GSM18001900_TX
R504
GSM_PA_RAMP
2.2K
C517
68p
C519 22n
8 C522
p
2.7p
L519
5.6nH
C532
L522
51p
2.7nH
Test Point (RF Rx Block)
DCS RX.
EGSM RX.
+VPWR
C524 C523
100u
33p
Schematic of GSM/DCS/PCS Rx Block
- 96 -
PCS RX.
1930-1990 MHz
L513
3.9nH
1805-1880 MHz
C515
1000p
L516
CP2_OUT
3.9nH
925-960 MHz
R507 100
C525
(1%)
1000p
C527
120p
MQW5V0C869M U503 FB500
L504
2.7nH
L505
12nH
C505
1000p
L508
12nH
L511
2.7nH
VREG_RFTX_2.85V
C509
33p
R502 R503
(1%)
4.7K 4.3K
680p C514
C511 6.8n
(PPS)
C516
0.01u
CP_HOLD2
29
CP2
30
VDDA9
31
RX_VCO_IN
RX_VCO_IN
R506 32
R_BIAS
11K (1%) 33
GSM1800_INN
34
GSM1800_INP RTR
35
VDDA10 U
36
GSM900_INP
37
GSM900_INN
38
VDDA11
R508 0 39
TX_MOD_CP
40
VDDA12
41
C528 TX_VCO_FB
R511 33
42
330p
C533
C531
82p
(PPS)
5.6n