LG GU280 Service Manual page 40

4.3.1 Checking VCTCXO Circuit
Checking Flow
Check TP2
(VCC of X101)
Yes
Check TP3
0 < TP3 < 1.8V?
Yes
Waveform of TP1
Similar to waveform
Below?
End
Circuit Diagram
VREG_TCXO_2.85V
C107
100n
R113
TRK_LO_ADJ
Close to QSC
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No
Check U201
No
Check U201
No
Replace X101
1n
C106
TP2
TP1
2K
R104
100
C179
33n
Checking Points
X101 DSA321SCA
4 3
VDD OUT
1 2
VCONT GND
19.2MHz
C108
10n
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4. TROUBLE SHOOTING
TP1
TP1
19M_XTAL_IN
LGE Internal Use Only
TP2
TP3