Bomann
No Start – Control or Door Interlock Issue
Microwave display and lights work, but pressing START does nothing; no relay click or fan noise.
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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 door interlock switch, Blown internal line fuse, Faulty control PCB relay drive
How to Fix / Troubleshooting
Safety: Unplug the microwave before opening the cabinet.
- Step 1 – Check door: Ensure the door is fully closed and the door icon (if present) is not flashing. Try opening and closing the door firmly.
- Step 2 – Test other keys: See if other buttons (clock, timer, power level) respond. If only START is unresponsive, the keypad may be faulty.
- Step 3 – Door switches: Access and test the door interlock switches with a multimeter. Replace any that do not change state correctly.
- Step 4 – Internal fuse: Check the internal line fuse for continuity. If blown, investigate for underlying faults before replacing.
- Step 5 – Control PCB: If switches and fuse are good, the control PCB or relay may be defective and require replacement.
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Repair Difficulty
Medium
3/5
Required Part
Door Interlock Switch Set
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