[R-390] in rush current limiters

[Todd Bigelow - PS]

Barry Hauser wrote:

> 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

That makes sense - I don't have a 600 (yet), only a couple 500s and one with a
sailboat on the grill. In the 500 it was optional I *think*, or it was an
afterthought. In fact, either one of the rigs I have or one I passed on didn't
even have a place cut in the chassis for a socket - it was just that purty gold
hammertone paint. [-:

Seems they also had some kinda plug-in unit for using different voltages?
Again, this is only on the 500. Many differing variations here, some included
the nifty tube clips in the back, other didn't, etc. They're sure not in the
R-390 class, but I'm still amazed at how well they can suck in the signals!

BTW, I've got a couple of parts units here and (amazingly!) one of them had a
R-390 meter mounted in the front panel above the airplane dial. You just never
know!

~Boomer,  KA1KAQ