LG GS290 Service Manual page 88

GS290 Operational Description
4.12.2. Checking PLL Control signals
Checking Points
TP1 (RF_EN) TP3 (RF_CLK)
TP2 (RF_DATA)
Figure 5. Transceiver
RF Transceiver Circuit Diagram
FE2
33
VBIAS
34
VDDTX1V5 VDDRX2V8
35 20
TX1 VDDRX1V5
36 19
TX2 U500 VCO_RC
37 18
VDDTX2V8 VDDVCO2V8
38 PMB6272 17
VDDMIX2V8 EN
39 16
GND3 VDDXO2V8
40 15
FSYS1
14
GND4 GND1
41 13
X500 TSX-3225
4
GND2 HOT2
1
HOT1 GND1
26MHz
CLK26M
RF_CLK
RF_DA
QX
Q
IX
I
Figure 6. Transceiver Circuit
Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LG Electronics
U601
C506 C537 C536 C535
0.1u 0.1u 0.1u 0.1u
RF_EN
C516 1n
26MHZ_MCLK
C517
R508
47n TP1
820
3
2
TP2
TP3
89/136
4. TROUBLE SHOOTING
Checking Flow
EN Signal(TP1) is OK ?
Yes
DA(Data,TP2) is Normal ?
Yes
CLK(Clock,TP3) is Normal ?
Yes
Control Signal is OK.
See next page to check
Mobile SW & FEM.
Waveform
RF_DATA(TP3)
RF_CLK(TP2)
RF_EN(TP1)
Figure 7. PLL Control Waveform
- 89 -
Revision B
No
Check U500
Check U500
No
No
Check U500
LGE Internal Use Only
LGE Property