[Milsurplus] Those Troublesome ARC-2 Dynamotors

[James Young]

I have both an ARC-2 and also an ARC-2A, mounting tray and remote control
box. The -2A has been on the air, the -2 is proving a bit more troublesome
in the IF chain.

My problem is with one of the dynamotors; it is missing the HV brushes! Any
suggestions as to how to replace or replicate them? So, I have two working
dyno's and only one set of HV brushes. None in the spares capsule either.

Really neat if impractical radios.

73 de Jim W8MAQ

-----Original Message-----
From: milsurplus-bounces at mailman.qth.net
[mailto:milsurplus-bounces at mailman.qth.net]On Behalf Of David Stinson
Sent: Monday, November 07, 2011 7:18 AM
To: ARC-5 List; milsurplus at mailman.qth.net
Subject: [Milsurplus] Those Troublesome ARC-2 Dynamotors



----- Original Message -----
From: "Meir WF2U" <wf2u at ws19ops.com>
Subject: Re: ARC-2 Owners?


> The only ham mod (I got it this way) is that instead of the original
> antenna
> push terminal and porcelain or ceramic insulator, a previous owner
> put a UHF
> connector mounted on an  aluminum plate using the same holes as the
> original
> ceramic insulator.

I've had to repair this mod on two ARC-2 sets.
Sad thing is, the ARC-2 won't match 50-ohm coax
any better than an ARC-5.
You still need a series cap or balun etc.
to make it work.

God bless you guys who are going to restore the
dynamotor.  If you want proof that Collins,
despite so much good work, could really screw-up
a design,  take a look at the PTO band switching
in the ART-13 and at the dynamotor mounting
in the ARC-2.    The heavy ARC-2 dyno is a smooth
cylinder with a female connection socket on one side.
The ARC-2 chassis has a set of male pins to
engage the socket.  It's been 14 years since I messed
with this, so my memory is a little hazy, but I remember
the frustration.
Once you settle that dyno in, there is NO room for
fingers to adjust it and get the blated pins engaged.
Now, any engineer who hadn't been drinking
would have put some kind of guild on the
dyno and chassis to align the thing.  But nooooo.
IIRC, the pins aren't even straight down, but
at an angle!  And the dyno has a center of gravity
along the long axis which makes it want to rotate
with the connections mis-aligned,of course.
I lost most of my hair to raising 4 girls, but
a hank or two went to installing ARC-2 dynos.
I was going to try using a thin, wide strap to
lower the dynamotor into the slot, then rotate
it until the pins engaged, but I got lucky on about
the 87th try and got the angle right.

When you get ready to install your dynamotor,
be sure it's lubed and test correctly, because
God help ya if you have to do it twice ;-).

73 DE Dave AB5S

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