Daewoo Start Circuit / Door Interlock Logic Fault

Microwave display works but pressing START does nothing

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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 door switch not signaling closed, Defective START key on keypad, Loose keypad ribbon cable, Control PCB input failure

How to Fix / Troubleshooting

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

Step-by-step checks:

  • 1. Check door closure: Ensure the door is fully closed and latches firmly. Try pressing gently on the door while pressing START; if it works intermittently, suspect door switches or latch alignment.
  • 2. Test other keys: See if time setting and other function keys respond. If only START is unresponsive, the keypad may have a localized failure.
  • 3. Inspect keypad ribbon: Remove the control panel and reseat the keypad ribbon cable on the control PCB.
  • 4. Door switch test: Access the door switch assembly and test each switch with a multimeter for proper operation. Replace any defective switch.

Note: If multiple keys fail or the control board does not respond after these checks, the membrane keypad or control PCB may need replacement.

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Repair Difficulty

Medium 3/5

Required Part

Door Switch Assembly
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