[sdiy] Fixing humming transformers in 1u rack units

[cheater cheater]

> Toroidal transformers are a different matter.  Due to the shape of the
> core, they have much lower divergent flux.  BUT if you happen to, say,
> mount it with a bolt that runs through the center hole and connects to
> the chassis on both sides, this effectively adds another winding to the
> transformer.  You really don't want that to happen.

Why?
Will that work as a secondary winding in an ac/dc transformer?

D.