Re: Repair Oral B 3D Pulsating Toothbrush

"Nelson" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) .com...
> Braun Oral B 3D Pulsating Toothbrush, Model 4729
>
> OK, so I know it would be cheaper to just buy a new one but I like the
> challenge... and I just bought a pack of 7 replacement brushes... grrr!
> This model charges a rechargeable battery inductively and is sealed up
> tighter than a ... (supply your own metaphor).
>
> Anyone know how to disassemble one of these? I'm assuming the battery
> has reached the end of it's charging life cycle, but I have to open it
> up to find out. And if it has, I'll probably have to jury rig in a
> replacement since I can't find anyone selling replacement parts on the
> web. My guess is that Braun doesn't make them available.
>
> Google is pretty much worthless on this since it pushes all the
> advertising sites to the top.
>
> --
> Nelson
>
> ** Posted from http://www.teranews.com **
I recently took a similar unit apart, the charger post engages in the base
of the toothbrush and can be used to twist the bottom of the unit off and
the guts then slide out. Mine had an O ring seal so it would, theoretically,
be possible to reassemble it; the top bush on mine was so worn that it had
leaked and it wasn't worth the effort to clean up as it needed a new NiCd
anyway. Other similar units have a cross slot moulded into the base and a
matching, for want of a better word, screwdriver blade moulded on the
underside of the charging base; the dismantling procedure is similar.
Martin
--
martin<dot here>whybrow<at here>ntlworld<dot here>com

On Fri, 1 Aug 2008 01:13:05 +0100, "Martin Whybrow"
<(E-Mail Removed)> wrote:


>I recently took a similar unit apart, the charger post engages in the base
>of the toothbrush and can be used to twist the bottom of the unit off and
>the guts then slide out. Mine had an O ring seal so it would, theoretically,
>be possible to reassemble it;

Yes - my wife's OralB toothbrush has stopped working a couple of times and this
is how it opens. The main problem is corrosion. It has suffered a corroded main
pcb track (along the edge of the pcb)to the power FET - replaced with wire link.
Also corroded through charging coil wire at the pcb solder pad. I think the
charging coil wires were short to begin with but I was able to get some extra
length (forget how) so that it now opens without breaking them.
I sprayed the pcb with varnish a couple of years ago but it has recently been
playing up again so will have to dismantle again soon.
Couple of 74 series chips LV00 and LV4060. The timer stopped working so
suspecting leakage/corrosion again.


Geo