Vizio VOJ370F1A_MT5382_LGD Service Manual page 26

TROUBLE OF DC-DC CONVERTER
U14 pin 5 6 7 8
U16 pin1 & pin2
CONFIDENTIAL – DO NOT COPY
Start
J1 PIN10,11,12
Yes
J1 PIN 2,3,4
Yes
Yes
U15, U17,U22
Yes
U21 pin2
Yes
U19 pin2
Yes
END
No
The voltage is about + 5V(+5VSB)
1. Check power board
2. Check power cable, F1 & connection J1
3. Check U22 pin1 (+5VSB) & pin2 (+3V3SB)
The voltage is about + 12V while power switch on
No
1. Is J1 connection good
2. Check J1 Pin1 is up to about 3.3V (+3V3SB)?
3. Check power board
4. Check F2.
The voltage is about +5V while power switch on
No
1. Check F1 & U14
2. Check OPWRSB (R19)
3. Check U14 pin1&2 or pin 3&4, should have -1V more.
The voltage is about +3.3V
No
1. Check F1 & U14
2. Check U15, U17,U22
The voltage is about +1.2V while power switch on
No
1. Check F1 & U14
2. Check U21 pin2
The voltage is about +2.5V while power switch on
No
1.Check J1 Connect
2.Check U19 pin2
The voltage is about +12V to +5V (for Tuner) while power
No
switch on
1. Check F2
2. Check U16 pin1 (+12V_AP) & U16 pin2 (+5V_TUNER)
Page 9-5
File No. SG-0285