LG KP500 - Page 101

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5. Trouble shooting
- 102 -
5.15.3. Checking TX I/Q Signals
Check TX I/Q Signals(TP1~TP4)
Signals are
Normal ?
Replace
Transceiver
PMB6272(
U401)
Yes
No
TX Part is OK.
Check Base Band Circuit
or
Re-Download S/W and Cal
Checking Points
I
Q
I
Q
TX
TP4
TP3
TP2
TP1
2
G
N
D1
GN
D
2
4
1
HO
T
1
HOT2
3
2
6MHz
X
6
0
0 T
S
X-
3
2
25
46
C
7
4
246C
u1
.
0
028
7
0
6R
V
R
F
_
2
V
85
4
3
6
C
u
1.0
9
1
5V
1
X
R
DDV
02
8
V
2XRD
D
V
5V
1
X
T
DD
V
53
8
3
8V
2
XT
D
DV
7
1
8V
2
OCV
D
DV
8V
2
O
X
DD
V
5
1
X
O
1
1
1
2
X
O
X
3
0
R
X
1
X
2
7
R
X
2
R
X
2
X
2
8
R
X
3
2
4
2
5
R
X
3
X
R
X
4
2
2
2
3
R
X
4
X
6
3
1
X
T
73
2
XT
43
SAIBV
CR_O
C
V
81
3
1
V
D
D
B
I
A
S
2
V
8
8
V
D
D
D
I
G
1
V
5
V
D
D
D
I
G
2
V
8
5
2
1
V
D
D
L
N
A1
V
5
8
V2X
IM
DDV
93
A
X
2
B
3
4
B
X
C
L
K
7
6
D
A
61
N
E
F
E
1
3
2
2EF
33
41
1
SYSF
1
0
F
SY
S
2
F
SY
S
3
9
31
1
D
N
G
G
N
D
2
2
6
0
4
3DNG
4DNG
1
4
2
9
R
X
1
PMB6272
U601
EUSY0274801
A
1
T
B
_
M
6
2
A
D_FR
K
L
C_FR
XQ
Q
XI
I
Figure 17. TX I/Q
Figure 18. TX I/Q
Figure 19. TX I/Q Waveform
Checking Points
Checking Flow
TP1(I)
TP2(IX)
TP3(Q)
TP4(QX)