Microwave stops shortly after starting and displays E2 on the control panel.

Safety warning: Unplug the microwave before removing any panels. Internal components can store high voltage. Do not touch the high-voltage section (capacitor, transformer, magnetron). If unsure, call a professional.

Steps to address E2:

• 1. Allow the unit to cool: If the microwave has been used repeatedly, let it sit unplugged for 30–45 minutes. Ensure vents are not blocked by cabinets or objects. Plug back in and test. If E2 clears temporarily, overheating is likely.
• 2. Inspect ventilation: Check rear, side, and top vents for dust, grease, or obstructions. Clean with a soft brush and vacuum. Ensure there is adequate clearance around the microwave per Tristar installation guidelines.
• 3. Locate the cavity thermistor: On most Tristar countertop microwaves, the thermistor is mounted on or near the top or side of the cooking cavity, accessible after removing the outer cabinet.
• 4. Check wiring: Verify the thermistor connector is firmly seated on the control board and at the sensor. Look for burnt or pinched wires. Repair or replace damaged wiring.
• 5. Test the thermistor: Disconnect the thermistor and measure resistance at room temperature. Compare to Tristar service specs (commonly in the 50–300 kΩ range depending on design). If reading is open, shorted, or far out of spec, replace the thermistor.
• 6. Control board check: If the thermistor and wiring test good but E2 persists, the temperature sensing circuit on the control PCB may be defective. Replacement of the control PCB is recommended and should be done by a qualified technician.