If you get desperate, ZO still has pucks for sale on its website. So does Miami Ski Nautique, but they are both very high priced ($450+). I wonder if a puck from an old Perfect Pass system would work. There ought to be some of those available. Have you tried unplugging the pucks and plugging them back in? No guarantee, but sometimes that brings them back to life. Or reverse where they are plugged in.