Problem:
The GF grumbled one morning: “my toothbrush isn’t working right”. Crap!
A quick inspection revealed that the motor still works, but the brush itself doesn’t vibrate much. A new one is over $100, so I have nothing to lose by (attempting to) take this thing apart.
Cause:
It took a bit of disassembly to find the cause, but it is that the coils slip and contact the vibrating head, preventing it from vibrating properly.
Solution:
The bottom is a cap and the entire device pulls out through the bottom of the housing.
By using a fat screwdriver, I twisted the cap a bit to break it free and then gently pried it out. Once the assembly was out, I could see the problem – the coils had slipped and were touching the supposed-to-be-vibrating brush head.
To fix this, you need to loosen two screws that hold the coils captive and slide the coils down a bit, then tighten the screws. This sounds easier than it is. First you have to gently compress the little spring in the rubber isolator, then pry the coil section away from the circuit board section. The two sections are only joined by the two wires to the battery, so be careful here.
Compress the spring, then gently pull the plastic circuitry away from the coil housing.
At this point, you can sort of fold the coil housing 90 degrees to the battery housing and easily see the screws on each side of the base of the coils.
You want to loosen both screws a couple of turns, then use a small screwdriver to pry apart the strong magnet pulling the coils up to the brush head, then while there’s a decent gap between the two, you want to tighten the screws back down.
Once this is done, line up the slots and tabs, compress the spring and reassemble the unit, test it and then insert the whole contraption back into the housing. Before you push it shut, ensure the seals are lined up and unharmed.
Cheers for the guide, I was in the exact same boat with my toothbrush and moving that coil worked like a charm. Only modification, I found using the plastic cheap “guitar pics” that come with electronic repair components on ebay worked great in popping the bottom cap off without scratching the seal with a screwdriver.