LG PRADA KE850 - Page 111

5. Trouble shooting
- 112 -
5.13.13 Checking FEM & Mobile SW
Mobile SW & FEM Circuit Diagram
GSM850
DCS
LB RF Input
Front End Module
EGSM
PCS
HB RF Input
C415
0.1u
C405
VRF2V85
C418
C403
0.75p
C413
L403
2.2nH
C416
KMS-506
SW401
ANT
G1
G2
RF
0
R403
C414
C417C412
C419
6
TX1G
8
TX2G
22
VCTRL1
VCTRL2
21
VCTRL3
20
VDD
3
EGSM_RX-
16
GMS_RX-
18
GND1
2
GND10
25 26
GND11
GND2
4
5
GND3
GND4
7
9
GND5
GND6
10
GND7
11 23
GND8 GND9
24
19
GSM_RX+
13
PCS_RX+
PCS_RX-
12
U401
YGHF-S006A
ANT
1
15
DCS_RX+
DCS_RX-
14
17
EGSM_RX+
33pC401
Checking Points
SW401
C401
R436 (ANT_SW2)
R437 (ANT_SW1)
R435 (ANT_SW3)
Figure 30. Mobile SW & FEM Circuit
Figure 31 Mobile SW & FEM
Table 5. FEM TX Control Logic
RX Mode EGSM DCS PCS
ANT_SW1 On On On
ANT_SW2 Off On On
ANT_SW3 Off Off Off