Samsung PL42E7SX/RCL Service Manual page 91

2) Troubleshooting Procedure in Abnormal Conditions
① No Display (Operating Voltage exist, but an doesn't exist on Screen)
▶ No Display is related with Y-MAIN, X-MAIN, Logic Main and so on.
This page shows you how to check the boards, and the following pages show you how to find the defective board.
[ Y-MAIN ]
Check several points
F5001 for VDD
FUSE
F5002 for Vs
OK
Q5008
FET/
Q5009
Q5010 DIODE
Q5013
OK
Y-MAIN
Normal State
Samsung Electronics
[ Logic Main ]
LED Blinks Check necessary points
YES
Check the LED
operation
YES NO
Check if internal is Check the
Default Black MICOM operation
Check if any address Check the ASIC
data output is detected Control Signal output
Check if the data
and control signals
between DDR & ASIC
are normal
OPEN
Replace the Board
SHORT
Replace the Board
No Display
[ Y-MAIN ] [ X-MAIN ]
Check necessary points
[ Logic Main ]
Check if power is supplied
( 5V, 3.3V )
NO
Check the
power connectivity
Check the FUSE
Check the
input voltage
If the input voltage is
abnormal, replace the
PSU and check it
again as this indicates
a PSU output error
[ X-MAIN ]
Check several points
F4000 for VCC
FUSE
F4003 for Vs
Q4010
FET/
Q4011
DIODE
Q4012
Q4015
X-MAIN
Normal State
Troubleshooting
OPEN
Replace the Board
OK
SHORT
Replace the Board
OK
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