[R-390] R390 knobs and more!

[Renée Deeter]

Hi Paul-
yes it still needs a ground, it was in Electric Radio, I think VK3??? 
had it on a web site.
If you cannot find the info I'll dig it up, scan it and E mail it to 
you. it is nothing special, typical current reg circuit + 1 diode and 
1000uf/50V on the input side.
it is the circuit I use, I like it better than any of the others, i 
added a gnd wire to one of the unused  pins on the socket, it is a half 
wave  rectifier, no need for the RMS metre- just measure the current on 
the bench then plug and go, and it all fits in on tube base including 
the heat sink.
Renée,K6FSB


Paul Galpin wrote:
> Hi all,
>
> THANKS to all who helped me on the knob placing question. As everybody
> agrees, then that must democratically be correct!
>
> So now, after sorting the knobs properly, I find I have 18 small (all
> lined), 11 Medium and 4 large, between the two sets. that's two down on the
> small, one up on the medium. It will work for me, as one set is missing the
> dial lock mechanism.
>
> but I'd still like to know how the Parts List got it so wrong!
>
> Next question.
>
> I have seen, somewhere, a current limiting circuit to replace the 3FT7 using
> just an LM317, a small bridge rectifier, and a specially chosen resistor to
> give an true RMS value of 300mA. It's one you have to build "blind" unless
> you have a true RMS meter to check it with. (I don't)  This circuit is a
> true replacement, as it only has the two connections, no ground needed.
>
> does anybody know where I could find it again?
>
> Paul G
> ZS2PG
>
>
>