Garbage disposal hums when switched on but the grinding plate does not turn; internal LED flashes twice repeatedly.

Safety first: Switch off the wall switch and isolate power at the breaker. Never work on a disposal that is still plugged in.

• Attempt manual freeing via hex socket: Many McAlpine disposals have a hex (Allen) socket in the centre of the motor base. Insert the correct size Allen key and rock it back and forth to free the jammed rotor. Do not use excessive force.
• Clear foreign objects from the chamber: With power off, use tongs or pliers (not your fingers) to remove any bones, cutlery, or hard debris from around the impellers and grinding ring.
• Check impeller arms: Inspect the McAlpine impeller arms for bending or being stuck. They should pivot slightly. If one is jammed, gently free it with pliers.
• Test operation: Restore power and briefly switch the unit on. If it spins freely without humming, run water and test with a small amount of soft food waste.

If the unit still only hums or trips the overload, the motor bearings or rotor may be seized and the motor assembly should be replaced.