CONFIDENTIAL
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DO NOT COPY
Page 9-5
File No. SG-0273
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TROUBLE
OF
DC-DC
CONVERTER
Start
J1
The voltage is about +5V (+5VSB)
1. Check power board
2. Check power cable, F4 & connection J1
3. Check U22 pin3 (+5VSB) & pin2 (+3V3SB)
J1 PIN 9,10,11
The voltage is about +5V while power switch on
1. Is J1 connection good
2. Check J1Pin9 is up to about 5V?
3. Check F15_ON is logic “H” (L90)
4. Check +15V at DC-DC Converter Board (L701)
U14 pin 5 6 7 8
The voltage is about +5V while power switch on
1. Check F4 & U14
2. Check OPWRSB is logic “L” (R10)
3. Check U14 pin1 & 3 is low 0.8V
U4, U14,U17 pin2
The voltage is about +3.3V
1. Check F6 & U1
2. Check U2, U4
U21 pin2
The voltage is about AV1.2V while power switch on
1. Check U21
2. Check U19 pin2
U19 pin2
The voltage is about DDRV (+2.5V) while power
switch on
1. Check J1 Connect
2. Check U19 pin2
U16 pin3
The voltage is about +12V to +5V_Tuner while
power switch on
1. Check F2
2. Check U16 pin1 (+12V) & pin3 (+5V_TUNER)
END