[Milsurplus] Those Troublesome ARC-2 Dynamotors

[J. Forster]

Some better hardware stores (Ace, True Value) have plastic boxes full of
small parts, like screws, circlips, etc. Check for one that has brushes.

Also, check out small motor (like vacuum cleaner) repair shops.

Get a big enough replecement and some sandpaper or a file.

Oh, it makes a mess.

-John

==========



> 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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