LG GD510 Service Manual page 82

GD510 Operational Description
5.12.4. Checking RX I/Q Signals
FE2
33
VBIAS
34
VDDTX1V5 VDDRX2V8
35 20
TX1 VDDRX1V5
U602
36 19
TX2 VCO_RC
PMB6272
37 18
VDDTX2V8 VDDVCO2V8
38 17
VDDMIX2V8 EN
39 16
GND3 VDDXO2V8
40 15
FSYS1
14
GND4 GND1
41 13
X601
4
GND2
1
HOT1
TP4(QX)
TP1(I) TP3(Q)
TP1(I)
TP2(IX) TP3(Q)
TP2(IX)
Figure 12. RX I/Q Circuit
LG Electronics
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
C650 C649 C623
100n 100n 100n
C627 47n
R603 820
RF_EN
C619 1n
26MHZ_MCLK
TSX-3225
3
HOT2
2
GND1
26MHz
TP4(QX)
BT_CLK
RF_CLK
RF_DA
QX
Q
IX
I
Checking Points
TP1(I)
TP3(Q)
TP2(IX)
U601
Figure 13. RX I/Q
Checking Flow
Check RX I/Q signals(TP1~TP4)
Signals are
Normal?
Yes
RX Part is OK.
Check Base Band Circuit
or
Re-Download S/W and Cal
I
Q
TP4(QX)
I
Q
Figure 14. RX I/Q Waveform
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5. Trouble shooting
Revision A
No
Replace
Transceiver
PMB6272(U602)
RX
LGE Property
LGE Internal Use Only