Swan Start Circuit / Relay Drive Failure

Microwave display is on but pressing Start does nothing; no relay click, no fan or light.

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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

Faulty Start button on keypad, Defective membrane keypad, Failed control PCB relay or driver, Door switches not signaling closed

How to Fix / Troubleshooting

Safety: Unplug before removing the control panel.

  • Step 1 – Check door status: Ensure the door is fully closed and latched. Try opening and closing firmly. If the display shows a door error icon, resolve that first.
  • Step 2 – Test keypad: Try other functions (e.g., clock set, power level). If multiple keys do not respond, the keypad may be faulty.
  • Step 3 – Inspect keypad ribbon: Remove the control panel and reseat the keypad ribbon cable on the control PCB.
  • Step 4 – Listen for relay: When pressing Start, listen for a faint click from inside. No click may indicate a failed relay or driver on the control PCB, which typically requires board replacement.
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Repair Difficulty

Medium 3/5

Required Part

Membrane Keypad Panel
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