The Ironman series of watches began in 1986, inspired by the Ironman Triathlon. The Ironman series was created to appeal to athletes by including a precise stopwatch and a higher level of durability and water resistance than many other watches of the time. In many digital watches, replacing the battery is a simple process of opening the back of the watch, replacing the battery and closing the watch up again. The Ironman series includes an extra step. To properly reset an Ironman watch, it must be shorted.
Remove the four screws securing the backplate to the watch frame and lift the backplate from the frame. Be careful not to damage the rubber O-ring around the edge of the backplate. Damaging the O-ring will remove the water resistance of the watch.
Take note of the small triangle on the lower left side of the battery cover label. The triangle is pointing to the AC pad that you will need to use to short the watch. If the label comes off, make sure to place it back in the same position.
Remove the battery cover screw and lift the cover away from the dead battery.
Remove the dead battery and insert a new CR2016 battery. Return the battery cover and secure it with the screw.
Straighten out a paper clip and then bend it into a thin “V” shape. The paper clip should now look similar to a pair of tweezers.
Touch one end of the paper clip to the top of the battery and touch the other end to the AC pad on the watch circuit board. This will short the watch and reset it. When the watch is properly reset, the face will display “12:00“.
Return the backplate and secure it with the four screws.