Microwave beeps and displays F1, often immediately on power-up or when trying to start a cook cycle; keypad may be unresponsive or act erratically.

Safety First: Unplug the microwave or switch off the dedicated circuit breaker before any disassembly. Microwaves contain a high-voltage capacitor that can retain a dangerous charge even when unplugged. Do not touch internal high-voltage components (capacitor, transformer, magnetron) unless you are trained and know how to safely discharge the capacitor.

• Power reset: Unplug the unit for 5–10 minutes, then plug back in. If F1 clears temporarily but returns when pressing certain buttons, the keypad is likely shorted.
• Check for moisture/contamination: If the error appeared after steam cooking or a spill, gently wipe the control panel surface with a slightly damp cloth, then dry thoroughly. Allow the unit to sit unplugged for several hours to dry out.
• Inspect ribbon cable: Remove the control panel (usually by removing the top grille and one or two mounting screws). Carefully disconnect and reseat the flat ribbon cable from the keypad to the control board. Look for corrosion, burnt spots, or cracks in the ribbon.
• Isolate keypad vs. board: With power disconnected, unplug the keypad ribbon from the control board. Restore power briefly: if F1 appears even with the keypad disconnected, the control board is likely faulty. If F1 does not appear until the keypad is reconnected, the keypad is the problem.
• Replace faulty part: If the keypad is integrated with the control panel, replace the entire control panel assembly. If separate, replace the membrane keypad or the main control board as indicated by your tests.

If you are not comfortable removing the control panel or working near high-voltage components, contact a qualified appliance technician.