Power Toothbrush Replacement After 12 Years

My Braun ultra plaque remover motorized toothbrush (type 4713) failed last week. I observed the recharge light fail to display when placed in the recharging base. Next, I noticed that the unit failed to recharge properly after a night of sitting in the recharging base. Sometime later, I noticed that the internal two-minute timer failed to stop the toothbrush after two minutes. Finally, the unit stopped recharging.

I have had this toothbrush unit since 1994, about 12 years. This is pretty good considering the web site says expectations are that the battery will last three to five years. It lasted me through my final year of high school, college, and now six years in California.


Today I purchased a new Braun AdvancePower power toothbrush. It looks identical to the old one, except it has a blue color scheme instead of green.

I noticed in the manual that it shares how to dispose of the nickel-cadmium rechargable battery that was in the old toothbrush, so I decided to take my old one apart and see how it operated.


This is a shot of the motor, the circuit board, the battery (under the circuit board), and the water-tight base seal, which houses the induction-type battery charger. Click the picture to see the high-res version.


Close-up of the base/induction charger. The coil on the right goes on top of this. Note the two copper wires attached to the circuit board from the base and the copper wire coil inside the base. Also note water has penetrated the base and left mineral deposits. Ick.


Circuit-board close-up. The LED is a square on the mid-right, next to the right-most integrated circuit. I don't know what the term is, but there's some gunk on the board that probably wasn't there when I bought it. You can see where the copper wires attach to the IC.


Motor (top-down). Those two plastic tabs on the top are the start/stop buttons. The spindle on the left is what attaches to the brush-head.


Motor (side). A better shot of the motor, and you can see the battery compartment.


Battery top and bottom. It's a NiCd battery, it doesn't say anything about capacity. The instructions which came with my new toothbrush say that a full charge takes 16 hours and lasts for 20 minutes. They also say, "Caution: Opening the handle will destroy the appliance and invalidate the guarantee. Note: You will not be able to place new batteries in the handle." Which is a half-truth, since you could probably swap out the batteries and use a soldering iron to re-attach the handle's connectors. You can see on the left where I cut the metal on each end to detach the battery so it could slide out the base of the handle. There are no markings on the ends.


An inside look at the handle after removing the battery. Note the two black spots inside the battery compartment near the motor. Not sure what those were for. The connector attached to the battery comes down from the top at that location, so it probably had something to do with electricity to the motor.


You can see the mineral deposits inside the handle cover here. Lovely.

That's it. Fun. Next up, a post on the fascinating topic of arranging my sock collection.