Microwave displays E9; unit may not respond to any input or may shut down unexpectedly.

Safety first: Unplug the microwave.

External power checks:

• Plug the microwave directly into a wall outlet, not a power strip or extension cord.
• Test the outlet with another high-wattage appliance to confirm it supplies stable power.
• If possible, try a different outlet on a separate circuit.

Internal checks (technician-level):

• Inspect the power cord where it enters the microwave for damage or looseness.
• Check the line filter board and wiring to the main control board for signs of burning or loose connectors.

If E9 persists and external power is good, the internal power supply section of the control board is likely faulty and the main control PCB will need replacement.