C-77
Samsung
Power Relay / Triac Error
Oven displays C-77 and may not heat or may shut off unexpectedly.
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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
Stuck or welded heating relay on main PCB, Failed triac controlling element power, Burnt relay contacts, PCB trace damage from overheating
How to Fix / Troubleshooting
Safety first: Turn off power at the breaker. Do not operate the oven until the fault is resolved, as a stuck relay can cause overheating.
- Visual inspection:
- Remove the rear panel and inspect the main relay control board.
- Look for burnt spots, melted plastic, or a burnt smell near the relays.
- Check for continuous heating:
- If elements stay hot even when the oven is off, a relay may be welded closed.
- Board replacement: Due to the high-voltage nature of the relays and the difficulty of safe repair, replace the entire main relay control board rather than attempting component-level repair.
- Professional service recommended: If you are not experienced with high-voltage electronics, contact a qualified technician to diagnose and replace the board.
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Repair Difficulty
Professional Required
5/5
Required Part
Main Relay Control Board
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