LG VX5400 Service Manual page 36

Replace X100 and then check C124, R104.
Figure 4.1.1 (a)
LGE Internal Use Only
Checking Flow
Checking Flow
Start
Check X100 pin3
Is it 19.2MHz? (Refer to
figure 4.1.1 (a))
NO
Check X100 pin4
Is it 2.8V? (Refer to
figure 4.1.1 (b))
YES
Is it similar?
NO
Replace Main B /D
19.23MHz
VCTCXO circuit is Ok . See next page
YES
The Problem ma y b e Logic part
R efer to Logic troubles hoot
NO
VCTCXO circuit is Ok . See next page
YES
Waveform
Waveform
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to check control signal .
to check control signal .
2.739V
Figure 4.1.1 (b)
Only for training and serving purposes