LG AR140B, Руководство по обслуживанию

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Only for training and service purposes
5. TROUBLE SHOOTING
5.12.4. Checking RX I/Q Signals
Figure 13. RX I/Q
Figure 14. RX I/Q Waveform
Checking Points
I
I
Q
Q
RX
TP4(QX)
TP3(Q)
TP2(IX)
TP1(I)
U400
Figure 12. RX I/Q Circuit
Check RX I/Q signals(TP1~TP4)
Signals are
Normal?
Replace
Transceiver
PMB6272(U400)
Yes
N
RX Part is OK.
Check Base Band Circuit
or
Re-Download S/W and Cal
Checking Flow
TP4(QX)
TP3(Q)
TP2(IX)
TP1(I)
TP4(QX)
TP3(Q)
TP2(IX)
TP1(I)
C419
100n C432
100n C404
100n
820
R403
C418
100n
C4
C406 47N
0
0
4
U
2
7
2
6
B
M
P
20
19
18
17
16
15
14
13
1
2
2
1
2
2
1
1
3
2
0
1
4
2
9
5
2
8
6
2
7
7
2
6
8
2
5
9
2
4
0
3
3
1
3
2
2
3
1
33
34
35
36
37
38
39
40
41
GND4
GND3
VDDMIX2V8
VDDTX2V8
TX2
TX1
VDDTX1V5
VBIAS
FE2
A
1
E
F
X
A
8
V
2
S
AI
B
D
D
V
B
X
1
X
R
X
B
1
X
R
8
V
2
GI
D
D
D
V
X
2
X
R
A
D
2
X
R
K
L
C
2
D
N
G
5
V
1
GI
D
D
D
V
X
3
X
R
3
S
Y
S
F
3
X
R
2
S
Y
S
F
X
4
X
R
O
X
4
X
R
X
O
X
5
V
1
A
N
L
D
D
V
GND1
FSYS1
VDDXO2V8
EN
VDDVCO2V8
VCO_RC
VDDRX1V5
VDDRX2V8
26MHZ
X400 NX3225SA
2 1
3
4
GND2 HOT2
HOT1 GND1
RF_DA
RF_CLK
QX
Q
IX
I
BT_CLK
TP1(I)
TP2(IX)
TP3(Q)
TP4(QX)