[R-390] Ballast Tubes

[Ed Berbari]

What value of resistor and wattage?

Ed, W9EJB


----- Original Message ----- 
From: "Rbethman" <rbethman at comcast.net>
To: "Bob Camp" <ham at cq.nu>
Cc: "r-390" <r-390 at mailman.qth.net>
Sent: Friday, July 02, 2004 9:32 PM
Subject: Re: [R-390] Ballast Tubes


> Hello all!
>
>     I bought my '67 EAC (R-390A) from an SK (WC3K) some three to four
> years ago.  In lieu of a ballast tube, it had the resistor in its place.
>
>     I brought it home, plugged it in, turned it on.  It still is
> running, and running just fine.
>
> Bob - N0DGN
>
> Bob Camp wrote:
>
> > Hi
> >
> > One thing you bring up that I should have mentioned. I have a couple
> > of radios that are running resistors and they seem to all work every
> > bit as well as the ones with ballast tubes in them.
> >
> >     Enjoy!
> >
> >         Bob Camp
> >         KB8TQ
> >
> >
> > On Jul 2, 2004, at 9:49 PM, Chuck Ochs wrote:
> >
> >> One must keep in mind that the R-390 was a "general purpose"
> >> receiver, which
> >> saw extensive shipboard use by the Navy during it's heyday. Power
aboard
> >> ships tends to be anything but stable. I know. I was a shipboard
> >> electrician
> >> on an LST during that nasty little war back in the sixties. We had
these
> >> radios on board, as did nearly every other ship in the Navy at that
> >> time.
> >> Using a ballast tube in the oscillator filament circuits was, at the
> >> time, a
> >> clever way to maintain stability during all those periods where the
line
> >> voltage sagged from operating such heavy electrical loads as gun
> >> turrets.
> >> The regulation of ships generators of the period was very slow by
> >> today's
> >> standards. IMHO, there is little ( probably NO) need for this
regulation
> >> scheme given a radio running on modern "shore power".
> >> A few years ago, the ballast on my VERY early R-390 died, and I simply
> >> replaced it with a resistor. I did not notice any change in operation
> >> whatsoever. It has been running this way for several years now.
> >> Chuck N1LNH
> >>
> <                      Bob Bethman - N0DGN
> +-------------------------------+----------------------------------+
> | N0DGN AMRadio Manassas, VA    |    REAL Tube Radio and AM        |
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