Power surges are commonly blamed when controls go bad on high-end units. I am not sure how often this is an accurate diagnosis versus how often this is just an easy scapegoat for unexplained parts failures. Plus … let us all be honest for a minute and acknowledge that as technicians we have all been guilty of condemning a control board because the system was operating abnormally and we did not understand what was happening … so therefore it must be that fancy looking control board.