Sharp No Start – Control or Door Interlock Issue

Microwave display and lights work, but pressing START does nothing (no relay click, no fan).

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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

Defective door interlock switch, Misaligned door latch, Failed START key on keypad, Control board not detecting door closed

How to Fix / Troubleshooting

Safety: Unplug the microwave before inspecting door switches or control panel.

Steps:

  • 1. Door check: Open and close the door firmly. Look for looseness or misalignment. If the door does not close squarely, the interlock switches may not engage.
  • 2. Test interior light and fan: On many Sharp models, the interior light and fan behavior changes when the door is closed. If the unit does not recognize the door closed state, a switch may be faulty.
  • 3. Keypad test: Try other keys (e.g., STOP/CLEAR, number keys). If some keys do not respond, the keypad may be defective.

Advanced: A technician can test the door switches with a multimeter and inspect the control board input circuits. Replace any faulty door switch set or keypad assembly with Sharp parts.

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Repair Difficulty

Hard 4/5

Required Part

Door Switch Assembly
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