Convert old electric toothbrush to plug-in

Electric toothbrushes are very nice, but the rechargeable NiCad batteries inside will wear out after a couple years of use. After my Sonicare toothbrush stopped holding a charge, I got a new one for Christmas (thanks, Santa!), and decided to try fixing my old one. Instead of just replacing the batteries with fresh cells, I decided to convert it to use a wall-wart-style outlet plugin.

Step 1 Remove the case

The two sides of the case are sealed pretty well (it's waterproof, or at least water/toothpaste resistant), so it might take a some effort to get it open. I'd suggest using a slotted screwdriver to carefully pry the case apart at the seam. You can also get a lot of leverage at the top, where the toothbrush head screws down over the bottom part. Try not to crack the whole case, or break it badly, as we'll want to glue it back together at the end. Once you get it open, you should see some coils, a circuit board, and a couple of batteries.