LG KP500 Service Manual page 95

5. Trouble shooting
5.14.1 Checking DCXO Circuit
Checking Points
TP1(C638) : 26MHz
Figure2. DCXO
DCXO Circuit Diagram
U601
PMB6272
C V O R _ C
EUSY0274801
8 1
D V D C V 2 O 8 V
7 1
N E
6 1
D V D X 2 O 8 V
5 1
F Y S 1 S
4 1
G N 1 D
3 1
X600 TSX- 3225
4
HOT2 3
GND2
1 HOT1 2
GND1
26MHz
Figure 3. DCXO Cicuit
6 2 M T B
LGE Internal Use Only
X600
6 C 8 3 1 0 0 p 0
6 R 7 0 6 C 0 4
8 0 2 4 n 7
TP1
Checking Flow
Is the waveform
of TP1(C638) similar to Fig.4?
Yes
DCXO Circuit is OK.
See next page to check
PLL Circuit.
R _ F N E
6 2 M Z H M _ C K L
TP1 (C638)
Figure 4. DCXO Waveform
Copyright © 2008 LG Electronics. Inc. All right reserved.
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No
Replace X600
Waveform
Only for training and service purposes