No Power - Samsung 400DXn Service Manual

4. Troubleshooting

4-2. No Power

When turning on the Power button after connecting the power, the LED at the front of the
-
Symptom
monitor does not operate.
Check the IP board power fuse and the IP board output power.
-
Check the connections for the IP board and the Main board inside the monitor.
-
Major
Check the LED of Power & IR function board and connections between the function assy and
-
checkpoints
main board.
Check the Main board power part and check also whether there is any abnormal output at other
-
output terminals.
Does the LED operate properly and
Diagnostics
Does 13V appear at Pin #5,6,7 of
Does 13V appear at C627, C644?
Dose 3.3V appear at Pin #1 of IC607?
Dose 1.8V appear at Pin #1 of IC610?
MICOM(IC300) operates abnormally.
Caution Make sure to disconnect the power before working on the IP board.
4-2
C644
CN601
C627
IC 607
Main Board Front
power assy and main board are
connected well?
Yes
CN601?
Yes
Yes
Yes
Yes
Replace the Main Board.
Main Board Back
Change the power function
No
assy or Reconnect the cable.
Check the IP Board and
No
connection.
Check the peripheral circuit of
No
CN601.
Replace IC607
No
Replace IC610
No
IC610