Microwave will not start; display works but pressing START does nothing or beeps and cancels.

Safety first: Unplug the Zanussi microwave from the mains. High voltage is present inside even when unplugged; do not touch the capacitor or magnetron area unless you are trained.

• Check door closure: Ensure the door closes fully and evenly. Inspect the plastic latch hooks on the door for cracks or deformation.
• Test door switches (interlocks): Remove the outer cabinet (usually several screws at the back and sides). Locate the door interlock switch cluster near the latch openings. With the door open and closed, use a multimeter on continuity to test each microswitch. A switch that does not change state (open/closed) when the door moves is faulty.
• Inspect wiring: Check the wiring harness and spade connectors to the switches for burning, looseness, or corrosion. Reseat any loose connectors.
• Replace faulty switch: If a switch fails continuity tests or shows signs of heat damage, replace it with a Zanussi-compatible door interlock switch of the same rating and terminal layout.
• Reassemble and test: Refit the cabinet, ensuring no wires are pinched. Plug in and test with a cup of water.

If you are not comfortable working around high-voltage appliances, contact a qualified Zanussi service technician.