I feel a little ashamed asking this question here, as it isn't really a
proper electronics question, but not finding any better place to ask it,
here goes. I'm trying to revive my trusty old electric drill (Craftsman
3/8" variable-speed reversible, all metal, not plastic, thank you very
much). Years ago the speed control crapped out, and I ordered a
replacement from Sears. When I put the new one in, the drill worked, but
not very well: a lot of sparking from the brushes and erratic operation,
like stalling and having to spin the shaft to get it running again.

So far as I can tell there's nothing mechanically wrong with it. Like a
lot of things from the past, it's built like the proverbial brick
****house. I cleaned the commutator; the brushes are solid and clean,
bearings well-lubed and free-spinning.

I think I just screwed up wiring the damn thing together. I have no
diagram, and followed what I *thought* was the way it was originally,
but apparently I've done something stupid.

The way it's wired now puts the field and commutator in series, which I
believe is correct for this type of universal motor. I tried reversing
one set of connections, but that didn't help, or even seem to make much
difference at all.

Does anyone know how these things get wired? Anyone have a wiring
diagram for this, or similar, drill?

Any help appreciated.


--
Pierre, mon ami. Jetez vous une plus de Scientologiste
dans le vat de l'acide.

- from a posting in alt.religion.scientology titled
"France recommends dissolving Scientologists"