Bush Start Circuit / Control Logic Fault

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

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.

Possible Causes

Faulty START button on keypad, Damaged membrane keypad, Faulty control PCB input circuit, Door not detected as closed by interlock switches

Safety: Unplug before removing the control panel.

Check door: Ensure the door is fully closed and latches firmly. Try pressing around the door frame while pressing START.
Test other buttons: If some keys work (e.g., clock set) but START does not, the keypad membrane may be worn.
Inspect keypad ribbon: Remove the control panel and reseat the flat ribbon cable between keypad and PCB.
Replace keypad: If START and other keys remain unresponsive, replace the membrane keypad or full fascia assembly.

Medium 3/5

Membrane Keypad Panel

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