You would need to ask if the watch is electronic or mechanical. If the battery needed to be changed, or if the mechanical spring had been wound. Were the hands moving or not? Were the digits changing or not? You would need to ask a LOT of questions to even begin to try to provide proper troubleshooting or repair suggestions--right? RIGHT???
Did you know that thousands of pieces of equipment and processes all use HMIs (Human-Machine Interfaces)? And you told us nothing about the equipment being controlled with the HMI, the type of HMI--nothing. NOTHING. And you listed yourself as an electrical engineer.
Try asking your question again--with a LOT more detail?