LG H990ds - Checking XO Block Frequency (WTR4905)

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3. TROUBLE SHOOTING
The output frequency(19.2MHz) of XO(X4100) is used as the reference one of WTR4905 and PM8996 internal VCO
3.1.2 Checking XO Block
Image
Checking Flow
Check TP1
Is it 19.2MHz?
START
The Problem may be
Logic partRefer to
Logic trouble shoot
Replace X4100 and then
check TP1
Is it 19.2MHz?
XO Circuit is OK.
Check next step
XO Circuit is OK.
Check next step
NO
NO
YES
YES
Circuit Diagram
TOP
U1401
(WTR4905)
TP1(XO_IN)
TP1(XO IN)
13