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LGE Internal Use Only
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
LGE Internal Use Only
(1) Checking Crystal Circuit
26 MHz O.K?
No
No
Crystal Circuit is OK
See next Page to check
Mobile SW
See next Page to check
Mobile SW
Yes
Change X501
Graph 4.2.1(a)
TEST POINT
CIRCUIT
WAVEFORM
Graph 4.2.1(b)
CHECKING FLOW
Figure 4.2.1
TP1
TP2
TP1
TP2
u
1
.
0
5
0
5
C
u
1
.
0
3
0
5
C
p
0
0
0
1
1
0
5
C
9
1
5
C
p
0
0
1
1
O
D
L
V
0
2
5
C
p
0
0
1
1
O
D
L
V
u
1
.
0
4
0
5
C
n
0
2
2
9
0
5
C
Q
B
B
_
C
C
V
4
2
E
F
_
C
C
V
1
7
1
F
E
R
_
C
C
V
12
VCC_TXVCO
13
VDD
15
VLDO1
16
VLDO2
VLDO3
9
RX1800
28
27
RX1800B
RX1900
26
RX1900B
25
RX850
32
31
RX850B
RX900
30
29
RX900B
K
L
C
S
6
5
A
T
A
D
S
N
E
S
7
11
TXOP_HI
TXOP_LO
10
C
N
_
C
F
A
V
8
1
14
VBAT
4
I
B
B
_
C
C
V
33
GND
2
I
B
I
3
8
C
N
3
2
Q
B
Q
2
2
0
2
N
I
F
E
R
B
N
I
F
E
R
9
1
P
O
_
F
E
R
1
2
T
X
E
V
_
3
9
V
2
1
0
5
U
8
4
5
6
D
A
1
0
1
0
8
2
0
Y
S
U
E
7
1
5
C
p
9
3
4
1
5
C
O
X
C
V
_
5
7
V
2
u
1
u
1
.
0
7
0
5
C
8
1
5
C
2
0
5
C
p
0
0
1
u
1
.
0
1
O
D
L
V
p
9
3
6
1
5
C
10
R503
6
0
5
C
p
7
2
T
A
B
V
M
6
2
T
B
_
M
6
2
S
S
S
N
I
N
Q
P
Q
P
I
TP2
TP1