The battery-powered WP-360 Water Flosser eventually slows down, so I buy
another and set the old one aside to fix later. Today is later, to avoid the
infection risk of a shopping trip and the cost of yet another new one. After
prying the ribbed ring out with a Swiss Army knife can opener they
disassemble easily with a small Phillips. Inside is two tabbed AA NiMH
cells, a DC motor and pump, all of which come apart by removing fairly large
screws, unlike the tiny ones on another of today's projects.

The on-line repair suggestions are about replacing the battery, but when I
took apart an old one for practice the batteries were still charged and the
motor had corroded and seized solid. The current, slow one worked fine after
I had opened it, which is typical for me. Maybe a bit of clogging dirt was
dislodged? I see the same thing with small engine carburetors.

Electrically the 3.17VAC input float-charges the NiMh cells through a series
diode. The motor on my good one draws about 1 Amp from a metered power
supply, disassembled on the bench without the pump load. The battery voltage
dropped from 2.8V (external test charge) to 2.2V before disassembly, 2.5V
after.

The motor pinion drives a crown gear with an eccentric for the pump piston.
The eccentric might have a trace of factory grease on it. I oiled everything
that moves with "safe for plastics" light oil since I didn't find a
different suggestion.

Has anyone else fixed one of these with good/bad results?

Jim Wilkins wrote:



Has anyone else fixed one of these with good/bad results?
I kept a Braun electric toothbrush working for YEARS past the expected
lifetime, with outboard batteries and a drop of oil on each motor bearing
every couple years. I'll bet a drop of oil on each end (if you can get to
the shaft at both ends) and let it soak in for a few hours will loosen the
motor up quite well. Eventually the brushes and or commutator wear away,
and that is the end of it.

Jon

"Jon Elson" wrote in message
...

Jim Wilkins wrote:

Has anyone else fixed one of these with good/bad results?
I kept a Braun electric toothbrush working for YEARS past the expected
lifetime, with outboard batteries and a drop of oil on each motor bearing
every couple years. I'll bet a drop of oil on each end (if you can get to
the shaft at both ends) and let it soak in for a few hours will loosen the
motor up quite well. Eventually the brushes and or commutator wear away,
and that is the end of it.

Jon
--------------------------------

I used a needle oiler from a hobby store which reached in past the crown
gear and under the pinion. The gear assembly separates from the motor easily
but I only did that on the frozen unit because inadequate gear tooth
engagement is a reported problem.

I've used turbine oil in a zoom spout bottle on the plain shaft bearings of
my megger and found that it needed re-oiling after a year on the shelf,
perhaps the thin oil evaporates? The crank drives a planetary speed
increaser on a concentric shaft, and becomes stiff if not oiled.

https://www.amazon.com/Insulation-Me...ct_top?ie=UTF8
It's a ripoff of the old Biddle megger. The idea is that if you shock
yourself you automatically stop cranking the high voltage generator.