In an age of cost cutting on products to compete in a very competitive market place, some producers seem to go too far. Reducing the quality of the product to the very edge in order to shave a few pennies. One consequence of this has been more battery leaks, with Duracell being by far the worst offender. Seriously, why does anyone still buy Duracell products! This time it was a friend who brought me the latest corrosive disaster, a Wii Balance Board with a mess in the battery compartment.
At least the balance board was easy to get apart, just a mess of screws on the back to remove, a few minutes with a phillips screwdriver. First remove the feet with three screws each, then the backplate with another ten screws. The unit is essentially a fancy bathroom scale with load cells in each foot. Rather nicely made, the engineers did a good job here.
Opening the case reveals the good news and the bad news. Good… The battery compartment is removable with just another couple screws. Bad… The damage here is severe, the small circuit board under the battery compartment is heavily corroded, traces and components destroyed. Good… The complex circuits for the unit, the processor and transmitter, are on another circuit board on the other side of the balance board and are untouched. Bad… The battery contact plating is gone, these are unusable. Even the wiring harness is damaged.
First to clear away the damaged bits and clean everything thoroughly. The battery compartment is dismantled and into a bowl of hot water to soak away the corrosive leakage from the batteries. Some folks panic at the idea of putting electronics into water. Truth is that most electronics components are rated for resistance to water and other solvents as washing is standard in many electronics manufacturing processes. As long as there is no power present you can wash most circuit boards. There are some exceptions here, I would not submerge an LCD display or any sort of battery. You must thoroughly dry everything before applying power.
A little gentle toothbrush action is required to remove some of the corrosion deposits on the little circuit board. As I do more damage becomes apparent… I will have to patch an number of traces with wire. Also being replaced is the sync switch. The wiring will have to be cut away and re-soldered after the last inch of damaged wire is trimmed back. A number of the pads are also in bad shape.
The battery contacts are replaced with some contacts out of some inexpensive AA battery holders I had on-hand. Not quite the neat spring arrangement of the originals, but they will work. A little RTV is needed to hold the new contacts in place, but I did not modify any plastic to make them fit.
All repairs complete, back together, and put some batteries in… It works! Well at least it powers up and the power LED flashes. I do not have a Wii to test it and will have to await news of proper testing after the unit has been returned.
Update: The unit is reported as working fine when returned to the owner.