E9 appears on the display and the unit will not start; sometimes accompanied by flickering display.

Safety first: Unplug the air fryer before opening any covers.

Steps to troubleshoot E9:

• 1. Power reset: Unplug the unit for at least 10 minutes to allow capacitors to discharge. Plug back in and check if E9 clears.
• 2. Try a different outlet: Plug the air fryer directly into another known‑good outlet (no surge strip) to rule out supply issues.
• 3. Inspect internal connectors: Remove the housing around the control board and display. Check all low‑voltage connectors between the display board and main control/power board. Reseat each connector firmly.
• 4. Look for board damage: Examine both sides of the main PCB for burn marks, cracked components, or bulging capacitors. Any visible damage usually means the board must be replaced.
• 5. Replace the control board: If wiring and connectors are intact and E9 persists, replace the main control board assembly. On some Hamilton Beach models, the display and control are a single combined board; replace as a unit.

Note: Firmware on consumer air fryers is not typically field‑reprogrammable. Persistent E9 almost always requires board replacement.