Samsung HPR4272CX/XAC, Service Manual

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Troubleshooting
Samsung Electronics 6-3
6-2-2 When the unit is repeatedly turned on and off
Symptom - The SMPS relay is repeatedly turned on and off.
Major Checklist
In general, the SMPS relay repeatedly turns on and off by the protection function due to a defect on a board connected to the
SMPS.
- Disconnect all cables from the SMPS, operate the SMPS alone and check if the SMPS works properly and if each voltage
output is correct.
- If the symptom continues even when SMPS is operated alone, replace the SMPS.
- If the symptom is not observed when operating the SMPS alone, find any defective ASSYs by connecting the cables one by
one.
Troubleshooting
Procedures
Caution
When separating and connecting the cables such as CN809 of the Main SMPS, CN1, CN2, CN3, CN4 and CN5 of DC-DC
SMPS, CN of the X Drive Board, and CN of the Y Drive Board, a spark may be generated by the electric charge of the high
capacity capacitor. Therefore, wait some time after separating the power cord from the unit.
Does the symptom continue
after connecting the power and
removing CN809 cable from
the Main SMPS?
Does the symptom continue
when separating the CN804-2
and CN803 cables from the
Main SMPS and shorting pins
4 and 5 of the CN804-2
Connector?
Replace the Main SMPS
Replace the Main Board
Does the symptom continue when
connecting the power after
connecting the CN809 cable and
removing the CN2, CN4 and CN5
cables from the DC-DC SMPS?
Reconnect all cables.
Does the symptom continue when
connecting the power after the CN4
cable to the DC-DC SMPS?
Does the symptom continue when
connecting the power after CN2
to the DC-DC SMPS?
Does the symptom continue when
connecting the power after
removing CN810 from the
Main SMPS?
Replace the DC-DC SMPS
Replace the X Drive Board
Replace the Y Drive Board
Replace the Logic Drive
Board