MasterChef Start Circuit / Control Input Failure

Microwave display works but pressing START does nothing; no relay click, no fan, no 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

Defective START key on keypad, Loose keypad ribbon cable, Failed control board input circuit, Active child lock mode

How to Fix / Troubleshooting

Safety first: Unplug the microwave before removing the control panel.

Steps:

  • 1. Check for child lock: Look for a lock icon on the display. Try holding STOP/CLEAR or LOCK for 3–5 seconds to toggle the lock.
  • 2. Test other keys: See if number keys, power level, and timer keys respond. If only START is unresponsive, the keypad is suspect.
  • 3. Power reset: Unplug for 5 minutes, then plug back in and test again.
  • 4. Inspect keypad cable (experienced DIYers): Remove the control panel and reseat the keypad ribbon cable on the control board.

Next steps: If START remains non-functional, replace the membrane keypad or complete control panel assembly.

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Repair Difficulty

Medium 3/5

Required Part

Membrane Keypad Panel
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