For a tuning knob you can use an old tv or radio knob, the type that
fit on the shaft that was split and had splines on it. Most of those
old knobw will fit on the arc 5.

Another way to do it is to remove the shell that is around the tuning
shaft. That will allow you to put a 1/4 inch shaft coupling on the arc
5 shaft. Then put a short shaft and knob on the other end and you are
all set.

73
Gary K4FMX

On Wed, 28 Feb 2007 19:31:11 +1300, cliff wright
wrote:

Dave wrote:
Rewire the filaments from 24 volt configuration to 12 volts.

You need +250 for plate voltage.

It's been 50+ years since I modified one, so I don't know the pin
assignments.

/s/ DD



genev wrote:

I just got an ARC 5 receiver and wonder if anyone has any tips on
modifying it; I had one in the 1960's, but can't remember what I had
to do to it. I think I replaced the dynamoter plug with a modern one,
but dont remember how I put the tuning knob on the front.
Also, what voltages are needed?
Thanks in advance for any info.
Richard
K1TAV



Hi!
The tuning needs a special socket in a splined multi pointed star formation.
The best source is of course the original remote cables, but finding
those would be a minor miracle by now. It just might be possible, if you
have well stocked hardware store near you to find a nearly identical
socket which could be made to fit. Don't forget the output impeadance of
the audio transformer is about 200 ohms to match the original crew
headsets. Actually by now I reckon that you might find that a lot of the
bypass and coupling caps in the cans along either side of the chassis
are leaky and may need replacing.
I'm not sure which RX you have, there are actually about 5 or 6
versions. The Hf ones above 3 MHz or so are very lacking in selectivity
with an IF frequency of 1.4 or 2.6 (I think) MHz.
I still have one of my first homebrew Ham RX's that I made back in the
1960's when I first came out to NZ.
It was a triple superhet, Ist IF tunable from 3.5-4MHz, 2nd IF 2xARC5
IFT's at 1.4MHZ and 3rd IF 2 stages of 85KHz using "Q5er" ARC5
transformers with 6 tuned circuits.
Worked very well but did have some image problems 2.8 MHz away from the
wanted signal.
Hope you can get it all going OK. I sem to remember several ideas
published back in the 1960's and 50's which you might be able to trace
on the web.
73's
Cliff Wright ZL1BDA ex G3NIA.