pedro wrote:

The Braun Triumph 3738 toothbrush and 3731 charger use an inductive
coupling arrangement to charge the toothbrush battery. Right now
SWMBO's unit isn't charging and I'm tasked with fixing it. Does
anyone know if this operates at line frequency or something higher?
(That will help sensing the field from the charging base to verify it
is operational before I disassemble the toothbrush itself.)
The old ones (no idea what model #) have a simple charging circuit
of a diode and a coil in the bottom of the handle, and 2 Ni-Cd
batteries. I can't get that size battery anymore, so I rigged two
larger cells outside and taped to the handle. It has worked
for some time. I used to replace the cells every 2-3 years when
the wouldn't hold charge anymore.

Jon