[Elecraft] KPA500 Transformer

[Eric Norris]

The torque spec is called out in the manual.  Why not use a torque wrench?
Can we please not resurrect the KPA500 hum thread already beat to death
multiple times years ago?  Or does everyone need to chime in yet again?

55 inch-pounds.

73 Eric WD6DBM

On Mon, Oct 19, 2020, 9:15 PM Bert <ve3nr at bell.net> wrote:

> Toroidal transformers cause very little acoustic hum, unless the core
> is not tightly wound or the copper wire windings are loose!
>
> If you have to tighten the mounting bolt with a torque wrench
> to get the transformer quiet, something is wrong!
>
> Bert VE3NR
>
>
>
>
> On 2020-10-19 19:59, Jim Spikes N4KH wrote:
> > Looking for details from anyone who resolved issues with excessive
> > transformer hum during transmit on a KPA-500.
> >
> >
> >
> > I have a hum mitigation application note sent from Elecraft tech support.
> > But the procedure recommended is pretty involved - removing front/side
> > panels, un-plugging connections, removing the transformer, changing
> > positions of the rubber discs, and putting it back together. Possibly
> more
> > than once, depending on the results.
> >
> >
> >
> > There is a risk of breaking something, and I'm not sure its going to
> solve
> > the problem if I'm successful. This is a new out of the box KPA500 kit.
> >
> >
> >
> > If anybody has any lessons learned I would appreciate hearing them.
> >
> >
> >
> > Jim, N4KH
> >
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