[R-390] line filter for EAC R390A

[Graham Baxter]

I isolated my line filter from the chassis using power transistor insulated
mounting bushes. I fitted a solder tag under one of the bushes and connected
a modern 4n7 class Y capacitor from it to the chassis. This mod can be
reversed in minutes, it cures the GFI (RCD in English) problems, and does
not much change the original appearance.
Graham
G8OAD

2009/7/28 Barry <n4buq at knology.net>

> > The 390/390A is not very susceptible to RF interference from crud on
> > the power line -- most objectionable interference comes in on the
> > antenna leads -- so doing without the filter entirely will be very
> > unlikely to degrade performance, unless you routinely run your radio
> > off a square-wave inverter or otherwise feed it god-awful dirty
> > power.  I consider it a best practice to replace the line filter with
> > a modern one, but I would not hesitate to remove it altogether,
> > confident that I would never be able to tell the difference in use.
> >
> > Best regards,
> >
> > Don
>
> I ran one of my R390As without a filter for a long time (until I replaced
> it with a modern line filter).  It might have responded to light switches a
> bit more than one with a good (read: modern) filter, but other than that, I
> doubt it made any difference.
>
> Barry - N4BUQ
>
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