DIAGNOSIS: Old oil and food debris are carbonizing in the heating chamber below the basket. This area is not accessible for cleaning.
FIX: Unplug and cool. Remove basket and pan. Add about an inch of water mixed with a tablespoon of white vinegar to the bottom of the main unit. Set temperature to 390°F and run for 10 minutes. Steam will loosen debris. Dump the water, wipe carefully with a damp cloth. Repeat if needed. Do this monthly if used frequently.
IF THAT DIDN'T WORK: Smoke is from oil dripping onto the heating element during cooking. You are using too much oil or foods with high natural fat content (like sausage). Place a slice of bread in the bottom pan to absorb drippings.
HEADS UP: Continuous heavy smoke can trigger the overheat protection and shut the unit down permanently. Clean the chamber after any smoky episode.