Kitchenaid kmhs120 microwave not shutting off — cooking a baked potato

Use only checks that match the exact appliance or system and its official guide.

1. Check 1

   From a safe position, note what remains active when the potato program appears finished: the display says END or still shows a time, only the vent/cooling fan runs, the turntable continues, the cavity light stays on, you hear microwave heating, or there is smoke or a burning smell. Do not put your hands inside while the oven is operating.

   Expected result: Only airflow remains with END displayed, or heat, turntable motion, a countdown, smoke, scorching, or an unresponsive control remains.

   Next step: For fan-only operation, allow the documented cooling period and monitor it without restarting. For continued cooking, smoke, burning odor, or an unresponsive control, press Stop/Unlock or open the door only if it opens normally, then disconnect power from a safe location and arrange service.

   Why this matters

   Why: END plus fan-only operation can be the documented cooling behavior. Continued heating, turntable motion, an active countdown, smoke, or a burnt potato is not explained by a normal fan delay.

2. Check 2

   Confirm the complete model suffix on the rating label and compare the Potato instructions in the matching KitchenAid manual. Check that the potato was pierced, the selected size was correct, the quantity was correct, and the turntable and potato placement matched the KMHS120 quick reference.

   Expected result: The full model matches a KMHS120 document, the Potato selection and quantity were correct, or the suffix/setting is uncertain or different.

   Next step: Use only the complete model's manual. If the suffix cannot be read or the display/program differs, stop using a borrowed keypad sequence and contact KitchenAid support or qualified service for the exact document.

   Why this matters

   Why: KitchenAid's KMHS120 quick reference distinguishes small and large potato quantities and requires piercing; a missing suffix or incorrect program selection can make the observed result impossible to compare safely with the manual.

3. Check 3

   After the appliance is cool and only if the previous event was fan-only with END, make one supervised comparison using a properly pierced potato and the exact KMHS120 quantity selection. Stay nearby and be ready to use Stop/Unlock; do not repeat a program that previously smoked or overcooked the food.

   Expected result: The program ends with END and only the fan runs briefly, the countdown continues beyond the expected end, the turntable keeps rotating, or the potato smokes or burns.

   Next step: Stop after the first abnormal comparison. Disconnect power safely and request qualified microwave service; do not remove the outer cover or attempt to test the magnetron, capacitor, relay, or interlock.

   Why this matters

   Why: A repeatable END/fan-only result supports normal cooling. A repeatable failure to end or continued cooking changes this from a food-preparation issue to a control, relay, door-interlock, or other service-level microwave fault.

4. Check 4

   If the fan remains on, determine whether it is the over-the-range vent fan cooling the microwave controls or a cavity/cooling fan described by the manual. Observe whether airflow stops on its own after the documented delay and whether the display has returned to the clock/standby state.

   Expected result: Airflow stops after the delay and the microwave is in standby, or airflow continues indefinitely, cycles with heating, or the controls remain in a cooking state.

   Next step: Monitor a normal cooling delay once. If it does not stop, operates with heat, or the display will not return to standby, leave the microwave off and schedule qualified service rather than repeatedly power-cycling it.

   Why this matters

   Why: A fan that finishes its cooling run while the oven is in standby is different from a control that keeps energizing cooking or never exits the program. A fan alone cannot establish a failed part.

5. Check 5

   Prepare the service handoff with the full model suffix, Potato size and quantity, whether the potato was pierced, the exact display at the apparent end, fan/turntable/heating behavior, elapsed cooling time, and any smoke, odor, sparking, or door issue. Do not open the microwave cabinet to collect more information.

   Expected result: The fault is reproducible, intermittent, or only occurs with the Potato preset while manual timed cooking ends normally.

   Next step: Leave the unit out of service for continued-cooking or safety symptoms and give the complete record to KitchenAid or a qualified microwave technician. Do not order a control board or keypad from the symptom alone.

   Why this matters

   Why: A Potato-only failure with normal manual shutdown points toward a preset/control or sensor-program issue, while failure of manual timed cooking or door-stop behavior raises a broader control/interlock concern. Only a technician can safely test those internal circuits.