[ARC5] T-18/ARC-5 schematic? And cleaning wrinkle paint?

[Michael Hanz]

On 2/15/2020 10:33 AM, Peter Bertini wrote:
> I just picked up a T18/ARC-5 (AN-ARC-5 with the RFC in the PA section.)
>
> It has several issues.  The entire area around the three octal sockets was
> been rewired to accommodate a 6V6 and 6AG7, and an xtal socket was
> mounted on the rear deck, near the power connector.  The power
> connector is now a chassis mount 11 pin plug :(  I have a socket
> that will work, but it is for the screen modulated style transmitters.
> I assume it would be almost impossible to find the correct part?

They are not common, but they do show up from time to time.  The process 
of installing it is not that easy, though - I've done it a couple of 
times and it does take some aforethought.  If I get time, I'l, try to 
put together a tutorial on the process.

With some care in removing it, you can also use the appropriate female 
connector from a triple coil box on any of the receivers, but you will 
need to put another female pin in the center of any of these.  From the 
sound of it, your transmitter isn't worth going to that trouble, though.

> I might have a transmitter that could be a donor, but I do not have a 
> good
> schematic for this transmitter, and by comparison I can some wiring
> differences on the PA sockets and in a few other areas.

Page 185-186 of the AN/ARC-5 manual.

> I do not have a good schematic for the AN-ARC-5, I do for my other sets.

Page 143-144 of the AN/ARC-5 manual.

As others have suggested, if you wish to get into the innards of the 
sets to the degree you have indicated, a manual is indispensable. As 
KK5F mentioned in his email of 12 Feb, there are free downloads 
available, as well as beautiful paper copies available from W5CAB for a 
very reasonable price.  A bit of study will add to your confidence in 
making modification reversals to the equipment.

> Except for the missing parts, extra rear apron holes, and wiring
> issues, the cabinet is in very good condition and the black wrinkle
> paint is also in good shape, but dusty and dirty.  And good
> methods to cleaning the surface, and perhaps adding a bit
> of shine to the paint so it looks like the unit just came out of the
> box?

There are a lot of different techniques around, each with their own 
adherents.  Cleaning is just the first step.  I like a marine cleaner 
that has an alkaline base, but others like Simple Green and the like.  
For the next step, leather care and black shoe polish products seem to 
be popular, along with the old standards like kerosene (smelly) and 
WD-40.  The most labor intensive method  is to use gloss black paint 
with a terry cloth towel after a thorough cleaning, but you have to be 
careful around engraved lettering and the like, using a Q-tip with a 
drop of thinner to restore the lettering.  I don't know a single 
location where you can find every method.  Sounds like a good research 
project for someone.

> Also, is anyone making replica accessory covers for the receiver
> front panel?

I assume you are referring to what generally comes under the rubric 
known as the "front panel adapter".  There are several of these, 
especially for the AN/ARC-5 sets (with differing prefixes like C-24, 
MX-19, MX-20, and MX-21, etc.)  The standard box usually delivered with 
the AN/ARC-5 receivers was the MX-21 adapter, and is simply a blank 
panel with a finger grab and a socket on the rear for jumpers.  The 
panel is easy to make with a small sheet metal brake, and the riveted 
finger grab can be pried off a damaged adapter or made on a small 
lathe.  But they too come up on auction from time to time.

> Some of the mods that have been done to 90 percent of the
> receivers I own need to be reversed. I am not a collector,
> but I'd to see these back to as original as possible.

That is what drives most of us here as well.  The sets were beautifully 
designed, and mods, while interesting to do and test, did not generally 
meet today's standards for evaluation of the results.  It's okay to have 
anecdotal or personal perception results, but "sounds better" seems to 
constitute the majority of the assessments over the years.

          73,
  - Mike  KC4TOS