Electrical Circuit Problem - Samsung SL-X7600GX Service Manual

4.8.7. Electrical circuit problem

No Problem Description
1 SMPS output voltage drop error
2 HDD makes a loud noise.
3 Networking is not working.
4 UI touch malfunction
5 Home screen icon is disappeared or UI screen is broken.
1) SMPS output voltage drop error
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Symptom : Some error messages occur on the OPE(C3-1312,S3-3121,M1-4111,M1-4211).
•
Cause : 24V channels output voltage drop to under 21.6V and 5V channels output is normal.
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Troubleshooting
1) Check all 24V output channels (24VS1, 24VS2, 24VS3, 24VS4) whether 24V voltage comes out or not.
2) If 24V voltage doesn't come out, check '24V on/off signal pin' on the main board.
a) The voltage at '24V on/off signal pin' is 0V. → Main board and signal is normal.
b) The voltage at signal pin is 4~5.3V → Main board and signal is abnormal.
3) If Main board and signal is normal and all 24V output channels are nearly 0V, check other parts( i.e. Fuser, motor,
scanner harness, etc.) driven by 24V voltage before replacing the SMPS.
4) If Main board and signal is normal and just one or two or three 24V output channels are nearly 0V, inspect some
harness from abnormal 24V output channel before replacing the SMPS.
5) If Main board and signal is abnormal and all 24V output channels are nearly 0V, inspect the harness, connector and
main board.
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4. Troubleshooting
Troubleshooting Page
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