- 94 -
LGE Internal Use Only
Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
GS290 Operational Description Revision B
LG Electronics
94/136
LGE Property
4.13.1. Checking VCTCXO Circuit
See RX Part “1. Checking DCXO Circuit”
4.13.2. Checking PLL Control Signal
See RX Part “2. Checking PLL Control Signal”
4.13.3. Checking TX I/Q Signals
Replace Transceiver
PMB6272(U500)
Check TX I/Q Signals(TP1~TP4)
Figure 17. TX I/Q Circuit
Yes
No
TX Part is OK.
Check Base Band Circuit or
Re-Download S/W and Cal
TP4(QX)
TP3(Q)
TP2(IX)
Signals are
Normal ?
Checking Points
Figure 18. TX I/Q
I
Q
I
Q
U500
TX
TP1(I)
TP2(IX)
TP3(Q TP4(QX
TP1(I)
G
Checking Flow
Figure 19. TX I/Q Waveform
GS290 Operational Description Revision B
LG Electronics
94/136
LGE Property
4.13.1. Checking VCTCXO Circuit
See RX Part “1. Checking DCXO Circuit”
4.13.2. Checking PLL Control Signal
See RX Part “2. Checking PLL Control Signal”
4.13.3. Checking TX I/Q Signals
Replace Transceiver
PMB6272(U500)
Check TX I/Q Signals(TP1~TP4)
Figure 17. TX I/Q Circuit
Yes
No
TX Part is OK.
Check Base Band Circuit or
Re-Download S/W and Cal
TP4(QX)
TP3(Q)
TP2(IX)
Signals are
Normal ?
Checking Points
Figure 18. TX I/Q
I
Q
I
Q
U500
TX
TP1(I)
TP2(IX)
TP3(Q TP4(QX
TP1(I)
G
Checking Flow
Figure 19. TX I/Q Waveform
26MHz
X500
TSX-3225
2
1
3
4
GND2
HOT2
HOT1
GND1
U500
PMB6272
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
EF
X
A
8
V2
S
AI
B
D
D
V
B
X1
X
R
X
B
1
X
R
8
V2
GI
D
D
D
V
X2
X
R
A
D
2
X
R
KL
C
2
D
N
G
5
V1
GI
D
D
D
V
X3
X
R
3
S
Y
SF
3
X
R
2
S
Y
SF
X4
X
R
O
X
4
X
R
X
O
X
5
V1
A
NL
D
D
V
GND1
FSYS1
VDDXO2V8
EN
VDDVCO2V8
VCO_RC
VDDRX1V5
VDDRX2V8
R508
RF_DA
RF_CLK
QX
Q
IX
I
CLK26M
TP1(I)
TP2(IX) TP(Q) TP4(QX)
