[Elecraft] KPA500 Hum when off?

[Jim Miller]

It's not fan noise. It's definitely 60hz hum likely due to transformer for
some reason. This was a factory assembled unit. I'll take the lid off and
check it out the bolting. I'm currently running on a shared household
circuit with who-knows-what connected elsewhere. The shack will get a
dedicated 20A circuit soon.

Thanks all

Jim


On Tue, Jun 11, 2013 at 11:58 AM, Jack Brindle <jackbrindle at me.com> wrote:

> Jim;
>
> Make sure the transformer is bolted down appropriately. If it works loose
> then it will cause the hum.
>
> Jack Brindle, W6FB
>
>
> On Jun 11, 2013, at 7:51 AM, Jim Miller <jim at jtmiller.com> wrote:
>
> > I leave my KPA500 back panel switch in the ON position most of the time
> and
> > use the front panel switch to bring it to life.
> >
> > However in even when in the "Front panel off/Back panel on" state the
> > KPA500 will occasionally hum for a few seconds.
> >
> > Is this normal? Any suggested causes to worry about?
> >
> > Thanks
> >
> > jim ab3cv
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