[R-390] in rush current limiters

[Barry Hauser]

> I thought they had a little phenolic plug that inserted into the socket
when the tube wasn't
> used? I would guess it has the correct pins jumpered? I'll take a look in
mine over the
> Christmas holiday and see what it says. Seemed to me the 50A1 was an
optional thing only
> needed where current wasn't stable? It's in the manual I think.
>
> ~Boomer,  KA1KAQ

Boomer & gang ..

I don't think so on that -- I've got a bunch of T/O's -- various series.
All the 600 series I have or have seen came with the 50A1 -- which started
with the very late 500 series and the military version of the 500 -- R-520.
All the 600 series had it.  (500 was last of the round dial, 600 was the
sliderule dial).  That phenolic plug may be an aftermarket replacement or
someone's homebrew thing.

Check out Padgett's TO pages ... http://www2.gdi.net/~padgett/tubedto.htm

There's also something there about the selenium rectifier and ballast tube
replaced by a silicon rectifier, etc.

Barry