Microwave shows E7 and will not accept input or start

Safety first: Unplug the microwave before removing the control panel.

Step-by-step checks:

• 1. Inspect for moisture: If the microwave is installed above a range, steam can enter the control panel. Let the unit dry for several hours with the door open. Try again after drying.
• 2. Power reset: Unplug for 5–10 minutes, then reconnect and test. Sometimes the control board can lock up due to static or power fluctuations.
• 3. Remove control panel: Remove the mounting screws securing the control panel (often behind the vent grille or on the side). Carefully pull the panel forward.
• 4. Check ribbon cable: Locate the flat ribbon cable from the keypad to the control PCB. Disconnect and inspect for corrosion or damage. Reseat the cable firmly, ensuring it is straight and fully inserted.
• 5. Test keypad: If available, use the Daewoo service mode to test individual keys. If multiple or random keys fail, the membrane keypad is likely defective and should be replaced.
• 6. Replace parts as needed: If reseating the cable does not help, replace the keypad assembly. If a new keypad does not resolve E7, the control PCB may need replacement.

Note: Do not spray cleaners directly onto the control panel. Spray onto a cloth first to avoid liquid entering the electronics.