LG LG-K430DSF - 3.3 Checking DC-DC Block

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3. TROUBLE SHOOTING
3.3 Checking DC-DC Block
The DC-DC(MT6328, U4100) output voltages is used as the reference one of SKY77643-31
Checking Flow
Image
TP1
Main
Bot
TP2
U4100
TP1
Circuit Diagram
TP2
START
Check TP1
VBAT is OK?
NO
The Problem may be
Logic part
Refer to Logic trouble
shoot
YES
Check TP2
0.5V ≤ TP2 ≤ 4.2V ?
Check U4100 Physical
NO
Damage or soldering
condition
YES
Check next step