LG KP500 - Page 95

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5. Trouble shooting
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5.14.1 Checking DCXO Circuit
TP1(C638) : 26MHz
X600
Replace X600
No
Yes
DCXO Circuit is OK.
See next page to check
PLL Circuit.
Is the waveform
of TP1(C638) similar to Fig.4?
TP1 (C638)
Figure 4. DCXO Waveform
Figure2. DCXO
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
p
0
00
1
83
6
C
046
C
n7
4
028
7
0
6R
V
R
F
_
2
V
85
7
1
8V
2
OCV
D
DV
8V
2
O
X
DD
V
5
1
X
O
1
1
1
2
X
O
X
CR_O
C
V
81
8
V
D
D
D
I
G
1
V
5
C
L
K
7
6
D
A
61
N
E
41
1
SYSF
1
0
F
S
Y
S
2
F
SY
S
3
9
3
1
1
D
N
G
PMB6272
U601
EUSY0274801
T
BM
6
2
NE_F
R
KL
CM
_
ZH
M6
2
TP1
Figure 3. DCXO Cicuit
Waveform
DCXO Circuit Diagram
Checking Points Checking Flow