Popcorn machines use a ceramic heater to heat the oil, while popcorn warmers like the one above uses a light bulb to keep the product warm.
There is an actual heater in the Pop Sez machine. The light bulb is not the heater. I restore mine with the heaters unhooked and tell the buyer how to hook it up if he wants to use it. I don't want to be responsible for the warmer catching fire. They get really warm. They are probably safe but you never know how long someone might leave it on.