Has anybody ever seen one of these? I was called to this man's home to diagnose an ice-encrusted LARGE freezer containing all the produce of his summer garden. He was understandably concerned about wasting so much work and food. This is the culprit, a failed mechanical defrost timer. It's pretty inexpensive as appliance parts go and usually very reliable- unless roaches get access to the inside and get fried by the electrical contacts. Is one of your household appliances giving you grief? I can take away your pain. Call Dave at 601-310-4220.