Thanks to all for the tips. I ended up taking it apart and attaching a
temporary power cord. The coils measured less than one ohm, but both
were about the same. It did nothing at first, but then I unplugged it
and rotated the blade a bit, plugged it in, and it fired right up to
high speed, like a circular saw should, sounded normal. Not sure if I
have a bad spot on the commutator or not, or just needed to seat the
brushes. I will go down to the repair depot next week to buy a
replacement cord, and I should be in business.

It is different to be taking apart old equipment, with cloth insulation
on the wires, everything built like a tank, etc. Not designed for ease
of manufacturing, at least to my eyes. One of the surprises was that the
trigger switch interrupted both hot and neutral, not just the hot side,
but maybe that is more common than I think.

Richard


Richard Ferguson wrote:
I bought an ancient Skil Saw for a few bucks, thinking that I was going
to use it with a metal cutting blade to cut steel plate. (Obligatory
metal content).

When I got it home and plugged it in, the blade spun, but slowly and it
seemed to pick up speed gradually, kind of like a fan, not like circular
saws that I was familiar with. Then I heard and smelled a "pop" in the
cord near the saw, complete with a small burn hole in the cracked
insulation. It tripped the GFI outlet it was plugged into, so my guess
is that there was a short to ground in the cord.

The saw has an AC/DC motor, 12 amps, and is a model 825. My guess is
that it is around 50 years old. It is massive and heavy. It has an 8
inch blade, which seemed unusual to me.

My question is what to do with it. If the only problem was the cord,
that is not a big deal. I could visit my local repair depot and buy a
cord and perhaps brushes. However, the way it wound up slowly made me
think that there was another problem with it. I am not real enthused
about messing around with it if it is not likely to work more or less
right after a little work. What do you think? Should I throw it in the
trash or give it away on Craigs list? Or should I invest a few more
bucks in a cord and hope that solves the problem? I don't want to throw
good money after bad, but perhaps I can get it working right without too
much trouble.

I know a moderate amount about electricity, but am not familiar with
troubleshooting motors. I do have a VOM, and know how to use it.

Richard