The control panel showed no lights at all. Checked for voltage (dc) coming out of control board which I did have 14 volts which indicated the interface board was bad. The toughest part of the job was removing and taking apart the door and reassembly. You Tube and plenty of patience. The big problem was finding a new board as not one company had them in stock. I called A.P.P. and they said the boards were on back order and about 2 to 3 weeks out. I was going to have them contact me when they came in. The representative indicated if I waited until then there would be a good chance they would sell out before I got one and it would be best to order it now and it would be shipped direct from their supplier. I got the part in about a week to my surprise.