there are a lot of wires in it. Eight I think. if one is broken it might misread. You could call the Datamarine repair company - Google search for it. They can make you a new cable.

These are great instruments. I know the newer stuff has more bells and whistles but for accuracy and reliability they can't be beat. Whatever you do don't scrap it. Send it to me if you don't want it. I could always use some spare parts.