Repairing Your Sonicare





Introduction: Repairing Your Sonicare

This thread has changed from a take-it-apart project to lots of advice on how to fix a Sonicare and put it back together. I hope all the great comments below help people bring their toothbrushes (or lockpicks or glass etchers or whatever) back to life.

Step 1: Overview

Circuitboard with on/off switch, two AA size rechargeable batteries under.

Step 2: Top

This is the top coil, which controls vibrations to the toothbrush head. I know the head has magnets on it, but how does it work...?

Step 3: Getting Ready to Remove Solder

Here are the 8 points that have to be removed from the base. The 4 in a row are the connections for the top head; the 2 under that are the battery power leads. The bottom 2 are the recharger leads. Note all the corrosion...

Step 4: Finally!

Getting all the points loose was difficult, partly because many of the leads had wires soldered to them below the circuitboard and it seemed to replenish the solder I removed. I heat sinked with alligator clips and paper clips in the tighter spots.

Step 5: Circuitboard and Battery Pack

lines show corresponding leads.

Step 6: Corrosion

I tried to get it off with a toothbrush (don't tell my girlfriend!) but had to scrape it instead. Here's what it looked like...

Step 7: Semi-cleaned Circuitboard

And here's what the board looked like after I scraped off the corrosion. It looks like I might have damaged by overheating while trying to remove the solder, too. Beyond hope? If I cleaned it would it still work?

Step 8: Just for Anyone Who's Curious...

Here's what's under the blue capacitor (?)

Another note for anyone who's interested in changing the batteries: they are a standard size but they are epoxied into the base with the same stuff that holds the coils. Remove them by cutting away the plastic film surrounding the cells, remove the cells, and then pull out the plastic.



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Questions & Answers


Please Can somebody tell me what this part is and where I could buy them in the UK.

Note please see my other post on this thread - im still getting to grips with the forum - sorry.

It's an inductive coil, simply magnet wire wound around a core. You should test the continuity of the posts with a multi-meter to make sure there is no break in the wire. If that is fine there is probably not a problem with it. It is far more likely that your batteries have failed. You can test them with the voltage meter of the multi-meter. If they are less than 1V they are most likely garbage and need to be replaced. They can be put into a AA Ni-Mh charger to see if they will charge.

Hi all, I would really love some help, and am really glad I have come across this website, can't believe I have never seen this before. I am a final year product design student at university in the UK, and I am designing a product which needs an induction charger like what is used on a toothbrush. So my question is what do I type in to find a condmuctive charging component/full kit like what is highlighted in the attached picture? Also, could youn recommend any UK based suppliers of such parts?

Really appreciate any help on this.

Best Regards,


After leaving the unit on the charging base overnight now when I press the On/Off button the unit runs at high vibration speed for approximately 10 seconds then changes to a lower vibration speed for about 2 or 3 seconds then shuts off.

I am able to select the various modes available as indicated by the LED's (cleaning, massage, etc. etc..)

I have also pressed the On/Off button for 5 seconds while the unit is on the charging base and heard 2 beeps (although this action now seems to alternate between the On/Off button and the Mode button??...)

The LED's light and the unit activates, the battery appears to hold a charge but it seems to be stuck in some kind of logic that I don't understand.

I have also pried out the negative end of the battery to remove all power to the circuit board but no change.

Can anyone tell me how to reset this unit properly or explain what it's doing?
And what my next steps could/should be?

Thanks for any help/information in advance.

Are you sure your batteries still hold a charge?

Most of the time, only the first cell of a NiCad battery pack is bad.  

NiCads develop "wiskers" which can be fixed/destroyed by running higher than the normal voltage of 1.2v across them intermittently.  

It is greener to try to fix it rather than replacing it.  

In this instance it was also much easier than desoldering and replacing the battery.

I usually use a 5V wallbrick and some tape to attach leads from the 5V plug end.

I was able to fix mine with the battery in place.  1.3V after I  "sparked" the bad cell with 5V.

Taking the sonicare apart was the most painful part.  It was a bloody affair after the utility knife slipped.

The plastic also fractured. Now I have to make sure moisture does not get into it.

After four years, you're not likely to comment, but maybe someone else will. I have an "original" Sonicare. Have opened it, and can see the batteries under the green board. Can't see getting them out. I don't know what a wallbrick is or how you would attach it to the battery to "spark" the bad cell. Is this dangerous? I doubt it.

Like magic. But I still don't like it that they don't let us replace the batteries without the rigmarole. Boo to Sonicare! Careful with that axe Eugene. Thanks for the post. I saved about $60.