Samsung PS42E7SX, Service Manual

Page: 98 / 104

Troubleshooting
Samsung Electronics 6-9
No Display
[ Y-MAIN ]
Check necessary points
[ Logic Main ]
LED Blinks
[ X-MAIN ]
Check necessary points
[ Logic Main ]
Check if power is supplied
( 5V, 3.3V )
Check the LED
operation
Check if internal is
Default Black
Check the
MICOM operation
Check the
power connectivity
Check if any address
data output is detected
Check the ASIC
Control Signal output
Check if the data
and control signals
between DDR & ASIC
are normal
If the input voltage is
abnormal, replace the
PSU and check it
again as this indicates
a PSU output error
Check the FUSE
Check the
input voltage
YES NO
YES NO
[ Y-MAIN ]
Check several points
FUSE
FET/
DIODE
Y-MAIN
Normal State
Replace the Board
Replace the Board
OK
OPEN
SHORT
OK
F5001 for VDD
F5002 for Vs
Q5008
Q5009
Q5010
Q5013
[ X-MAIN ]
Check several points
FUSE
FET/
DIODE
X-MAIN
Normal State
Replace the Board
Replace the Board
OK
OPEN
SHORT
OK
F4000 for VCC
F4003 for Vs
Q4010
Q4011
Q4012
Q4015
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.