LG L15V26 - 30 Power Supply Voltage Diagram

Directview LCD Training 25 Circuit Descriptions
CIRCUIT DESCRIPTIONS
PCB
TROUBLESHOOTING DIAGRAM
30” POWER SUPPLY
VOLTAGE DIAGRAM
Scaler
(Format
Converter)
Main
Microcontroller
24V
Audio
Processor
Audio
Amp
Analog/
Digital
Converter
Video
Decoder
LVDS Transmitter
(LCD Driver)
LCD Panel
18V
5V
7V
Power
Supply
Ballast
(DC to AC
Inverter)
De-Interlacer
TMDS
Receiver
No Power
- 30" LCD -
Power
from all inputs
Power from
+24V/+12V/+18V in
110VAC input
Power
from +24V/
+12V/+18V
Power
from +18V
Power
from +5VS
B
C D E
Blown fuse
Rec ty fy i ng
circuit/EMI filter
error
Replace fuse and
check BD801,
Q801, Q802, Q804
Check BD801,
Q801, Q802, Q804
Yes
No
Yes
Yes
No
No
Yes Yes Yes
NoNo
No
Problem lies
elsewhere
No
No power from
+24V/+12V/+18V in
110VAC input
Drop of output
power due to error of
the PFC circuit
B
C
Problem lies
elsewhere
T801 Error
Error in peripheral
parts
Replace U901
(MC33368D) &
check/replace
Q801
No power from
+24V/+12V/+18V
Output terminal
shorted
#7 pin bias power
of U902 is abnormal
(normal: 15V-25V)
Check/replace
R941-R944, U902
(FAN7554), Q804
T803 Error
Replace T803
Check second
side parts for
pattern/output
terminal short
Problem lies
elsewhere
No No
Yes
Yes
No
No No No
Yes
Yes
Yes
Replace T803
Yes