Hi gerty and Robert,
I had one where the secondary opened up on me. I hacked it apart
with a razor knife. Made a mess of the case, so i discarded it.
I couldnt find any obvious reason for the open circuit in the secondary
and the primary still looked ok, so i hacked off the secondary turns
with a hacksaw which left only the primary.
Looped a few turns of heavy wire through the core, and viola,
i had a new current transformer! he he. I used it for years
to monitor current going through my microwave oven.
That was way back then however. Since then, i've found a new way
to hack into these welded cases...
I took a Dremel cutting disc and ground off all the teeth.
This was an actual saw blade about 5/8 inch diameter (not the big ones
made for their cutting tool) and these have teeth just like a big circular
saw blade, just much smaller, and these are made out of some sort
of very thin spring steel, not the composite cutoff discs found for
the Dremel too.
Anyway, after you grind off all the teeth you are left with a simple
disc with a hole in the middle and it is very very thin spring steel.
The hole of course is to mount onto a mandrel, and that gets
chucked in the Dremel chuck.
The thing is, when this type of disc is set to spin around 10k RPM or
higher the disc cuts through plastic like butter, removes very
little material, and leaves a nice clean edge on the plastic.
I found that cutting the little wall wart cases apart at the seams
with this tool not only very simple, but allows them to be glued
back together again if needed.
It may even be possible to use some sort of plastic weld to make
a nice job, but i havent tried this yet. I have used epoxy in the
past though. I havent been overly worried about the appearance
too much when done, but maybe you would be more concerned
about that, so maybe experiment with different glues/compounds.
Last one i did a while back for running a simple dc fan, i used
some epoxy putty to secure the wires coming out of it and seemed
to work pretty well except for the appearance of a blob of it
![Smile :smile:](./images/smilies/icon_smile.gif)
LEDs vs Bulbs, LEDs are winning.