LG KE520 Service Manual page 56

4.2.1.4 RF Main Transceiver Circuit
C739
C740
U401
U400
C401
0.01u
C404
3.9p
C408
22p
A1
PCSLNAI
B1
PCSLNAIB
C2
PCSDCSGND
C1
DCSLNAI
D1
DCSLNAIB
D2
DCSG90GND
E1
G90LNAI
F1
G90LNAIB
E2
R2A60167BG
G90G85GND
G1
G85LNAI
H1
G85LNAIB
F2
G85GND
G2
GNDLNA_TX1
H2
TXON
E3
GNDDMIXIN
J2
DMIXIN
J1
DMIXINB
m
C426
22p
m
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
TP 1
0.01u
C402
3.9p
C407
C406
68p
33nF
C405
0.1u
B9
XON
C8
GNDVCXO_OR
D7
VOUTEF2
C9
VCCVCXO
D8
VOUTEF1
D9
VCCLOGIC2
E7
U401
GNDLOGIC
F7
CLOGIC1
E9
VCCLOGIC1
E8
STROBE
F8
SYSCLK
F9
RXTXDATA
G7
RXTXEN
G6
TEST1
G9
CTRLEN
G8
CTRLDATA
H9
CTRLCLK
C424 0.01u
<Fig.3> Main Transceiver Circuit Diagram
- 57 -
4. TROUBLE SHOOTING
SYSCLK
U400
1
L402
_OE
2 A
8.2nH 3
GND
SN74LVC1G125DRLR
0.1u
C416
SLICER_IN
VCC_SYN
0.01u C420 0.01u
C419
VRIO
DIGITALRF_DATA
DIGITALRF_ENABLE
DIGITALRF_RF_CS
DIGITALRF_RF_DATA
DIGITALRF_RF_CLK
SYSCLKEN
C_VCCRF
VRIO
C409
0.01u
VCC
5
4
SYSCLK
Y
TP1
LGE Internal Use Only