LG GM360i Service Manual page 90

4.12.4 Checking RX I/Q Signals
FE2
33
VBIAS
34
VDDTX1V5 VDDRX2V8
35
TX1 VDDRX1V5
36
TX2 U501 VCO_RC
37
VDDTX2V8 VDDVCO2V8
38
VDDMIX2V8 EN
39
GND3 VDDXO2V8
40
FSYS1
GND4 GND1
41
X501
TP1(I) TP4(QX) 4
GND2
1
HOT1
26MHz
TP4(QX)
TP2(IX) TP(Q)
TP1(I)
TP2(IX TP3(Q
26MHZ_BT
RF_CLK
RF_DA
QX
Q
IX
I
Figure 12. RX I/Q Circuit
Checking Points
TP4(QX
Figure 13. RX I/Q
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Only for training and service purposes
Checking Flow
Check RX I/Q signals(TP1~TP4)
20
19
18
17
RF_EN
16
C534 0.001uF
15
26MHZ_MCLK
14
13
C535
R510
0.047uF
820ohms
TSX-3225
3
HOT2
2
GND1
Check Base Band Circuit
Re-Download S/W and Cal
TP3(Q TP2(IX) TP1(I)
U501
95/147
Signals are
Normal?
Yes
RX Part is OK.
or
I
Q
RX
I
Q
Figure 14. RX I/Q Waveform
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4. TROUBLE SHOOTING
Replace
No
Transceiver
PMB6272(U501)
LGE Internal Use Only
LGE Property