LG GT350 - Page 93

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Only for training and service purposes
4. TROUBLE SHOOTING
LG Electronics 90/115 LGE Property
4.12.4 Checking RX I/Q Signals
Figure 13. RX I/Q
Checking Points
TP1(I)TP2(IX)
I
I
Q
Q
RX
U601
Check RX I/Q signals(TP1~TP4)
T
P2(IX
T
P3(Q
T
P4(QX)
Figure 12. RX I/Q Circuit
Signals are
Normal?
RX Part is OK.
Check Base Band Circuit
or
Re
-
Download S/W and Cal
Yes
Replace Transceiver
PMB6272(U601)
No
T
P1(I)
Checking Flow
TP4(QX TP3(Q
Figure 14. RX I/Q Waveform
X601
26MHZ
TSX-3225
21
3
4
GND2 HOT2
HOT1 GND1
U601
PMB6272
20
19
18
17
16
15
14
13
12
2
1
22
11
32
01
42
9
528 6
2
7
726
8
2
5
924 033
13
2
23
1
33
34
35
36
37
38
39
40
41
GND4
GND3
VDDMIX2V8
VDDTX2V8
TX2
TX1
VDDTX1V5
VBIAS
FE2
A 1EF
XA 8V2SAIBDDV
B X1X
R
XB
1XR
8V2
G
IDD
DV X
2X
R
A
D
2XR
K
L
C 2
DN
G
5V
1GI
D
D
DV
X3
X
R
3SYS
F 3XR
2SYSF X4X
R
OX 4X
R
X
OX 5V
1AN
L
D
DV
GND1
FSYS1
VDDXO2V8
EN
VDDVCO2V8
VCO_RC
VDDRX1V5
VDDRX2V8
0.001uFC616
0.047uF
C617
R612
820
RF_EN
RF_DA
RF_CLK
26MHZ_MCLK
QX
Q
IX
I
26MHZ_BT
TP1(I)
TP2(IX)
TP3(Q)
TP4(QX)