Hi,Welcome to Just Answer, My name is XXXXX XXXXX forward to helping you today.
the control board is bad, the problem is microwaves and dangerous to work on, even with the breaker off they can store a lethal amount of voltage, I can give you a general idea of the part cost however. the board runs around $166.00 and is most likely the cause. this has relays that stick. they are part of the board, the part # XXXXX XXXXX .