LG KP500 Service Manual page 99

5. Trouble shooting
5.14.4 Checking RX I/Q Signals
F 2 E
3 3
V I B S A
4 3
D V T D 1 X 5 V
U601
5 3
T 1 X
PMB6272
6 3
T 2 X
EUSY0274801
7 3
D V T D 2 X 8 V
8 3
D V D I M 2 X 8 V
9 3
G N 3 D
0 4
G N 4 D
1 4
VRF_2V85
TP4(QX)
6 C 2 4
TP1(I)
. 0 u 1
TP3(Q)
TP2(IX)
Figure 12. RX I/Q Circuit
Checking Points
TP4
Figure 13. RX I/Q
LGE Internal Use Only
6 C 4 3
. 0 u 1
D V D R 2 X 8 V
0 2
D V D R 1 X 5 V
9 1
C V O R _ C
8 1
D V D C V 2 O 8 V
7 1
N E
6 1
D V D X 2 O 8 V
5 1
F Y S 1 S
4 1
G N 1 D
3 1
6 R 7 0 C 4 6
8 0 2 7 4
X600 TSX- 3225
4
HOT2 3
GND2
1 HOT1 2
GND1
26MHz
6 2 _ M T B
F R C _ K L
F R D _ A
Q X
Q
X I
I
TP3
TP2
TP1
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
RX
I
Q
Figure 14. RX I/Q Waveform
Copyright © 2008 LG Electronics. Inc. All right reserved.
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No
Replace
Transceiver
PMB6272(U601)
Only for training and service purposes