F4
Sharp
Voltage / Power Supply Abnormality
Dehumidifier displays F4 and will not start the compressor.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Input voltage out of range, internal power supply failure on main PCB, loose power cord connection, damaged surge components on PCB
How to Fix / Troubleshooting
Safety: Unplug the unit before inspection.
Steps:
- Check outlet: Verify the wall outlet voltage with a meter if possible, or test with another appliance. Avoid extension cords.
- Inspect power cord: Look for cuts, kinks, or burn marks. Replace the power cord if damaged.
- Internal inspection: Remove rear panel to access the main PCB. Look for burnt components near the AC input and power supply section.
- Reset: Some models have an internal fuse or thermal cutout. If blown, determine the cause before replacing.
- Replace PCB: If the power supply section is visibly damaged or F4 persists, replace the main control PCB.
Warning: Do not attempt to repair the switch-mode power supply at component level unless you are qualified; there is risk of electric shock.
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Repair Difficulty
Hard
4/5
Required Part
Main Control PCB
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