Microwave beeps and displays F1, will not start a cook cycle or stops shortly after starting.

Safety first: Unplug the microwave or switch off the dedicated circuit breaker before removing any panels. High-voltage components inside a microwave can retain a dangerous charge even when unplugged. Do not touch the magnetron, capacitor, or high-voltage wiring.

Step-by-step checks:

• Power reset: Disconnect power for 5–10 minutes, then restore power and see if F1 clears. If the code returns immediately without pressing any keys, the keypad or control is likely shorted.
• Check for stuck keys: Gently press each key on the control panel of your Monogram microwave and verify they all have a similar feel and return. If any key feels stuck or unresponsive, the membrane keypad is suspect.
• Inspect control panel ribbon cable: Remove the upper grille and control panel per the Monogram service manual. Carefully disconnect and reseat the flat ribbon cable from the keypad to the main control board. Look for corrosion, burnt spots, or kinks.
• Isolate keypad vs. control board: With power disconnected, unplug the keypad ribbon from the control board. Restore power briefly. If F1 no longer appears with the keypad disconnected, the keypad/control panel assembly is defective. If F1 still appears, the electronic control board is likely faulty.
• Replacement: Replace the control panel / keypad assembly or electronic control board using the exact Monogram part number from the model tag and parts diagram. Transfer any mounting hardware and reconnect all harnesses securely.

When to call a technician: If you are not comfortable removing the control panel or working around live voltage, contact an authorized Monogram service technician.