On 4 Sep 2024 at 18:52, David S wrote:

> Photos are attached

>

> TT6.jpg is the 1/4in audio jack, same kind of thing I see electric

> guitars use.  Been forever since I have seen one.

Notice first that the plug (not jack) is a TRS type ...

Tip - ring - sleeve

My guess would be that is the way the unit is connected

into the "local loop" -- which is generally a 120vDC source

with a big (power) limiting resistor which sets the "loop current" to either 60mA or 20mA ...  depending on how

the selector magnet is wired.

Often such a plug is wired using the tip and ring so that

the sleeve (and the sleeve of the jack into which it plugs)

is not hot with the 120vDC ...

I would strongly suggest that the first thing you do is

to use an ohmmeter and check if any of the three wires

on the plug go to terminals on the selector magnet. 

Actually, before that measure the resistance between

tip and ring

tip and sleeve

ring and sleeve

this can give you a clue what is on the other end of the wire!

if you DO get continuity between the plug wire(s) and the

selector magnet, that will immediately confirm it is the

loop plug.  If no continuity, then you'll have to physically

trace the plug's wire into the guts and see where it goes;

it may well go to the Electrical Service Unit -- which will

lead you to a fascinating expedition of discovery ...

> TT5.jpg is the bottom shelf area of

> this wall mount unit, which houses

> the paper spool and the "Electric

> Service Unit".  The 1.4in audio jack

> cable comes in on the right side as

> a grey cable, extends to the far left

> and enters behind the lower black

> cover panel.

OK, then the gray cable does NOT go

into the metal box "C" I presume.  It looks to me like it

goes in behind the black cover of the terminal strip; so

you will want to remove the black cover and determine

what terminals the gray cable goes to....   if you can find

ANY indication of a military or Bell System configuration

ID you might ask on Green Keys if anyone has the schematic

for that configuration.

The plug at "D" looks to me like an AC plug.

You will want to take the cover off box "C"

and see what is inside ... might be a heavy duty

"motor control" relay, OR something else.

You will spend a lot of project time playing

detective, trying to find out what is connected

to what ...  hopefully you are good at drawing

schematics and/or wiring diagrams !!

> There is disintegrating material on

> the interior walls which I assume

> could be sound dampening foam of

> some sort?  It crumbles to the

> touch. 

Yes, that WAS sound dampening foam!

and it is very common for it to disintegrate

over the years.

> The important stuff like wires and

> metal all appear in good shape, just

> dirty.

Before you apply any power to the unit,

and after you do your basic cleanup, you will

want to manually turn the fan on the motor

(be careful at first that you are turning in

the direction that causes the gears and

mainshaft to turn; if not, stop and turn the

other way).  You want to be able to manually

turn the motor long enough to be sure that

the main shaft and all the other 'stuff' is

working freely -- no sticking or binding.

 

> I may have been lucky in finding

> this wall mount unit, it appears to

> be uncommon, and coincidentally

> perfect for the application I have

> in mind.

wall mounts ARE quite rare...

your situation is called SERENDIPITY !!

> > btw, I have a mint (in original sealed foil packaging)

> > copy of TM 11-5820-402-10  Technical Manual

> > for AN/VRC-12, -44, -46, -48, -49 ...  rather than try

> > to pedal it on eBay for whatever, I'll slip it into the

> > box with the M28 manuals.

>

> Yes please, thank you so much,  I will put it to good use.

There was no space left in the M28 manual box to put

the TM 11 in, so it was in with the two rolls of paper.

The M28 box is full and is already sealed and addressed,

so I'd rather not take it all apart now. 

>

> >> Are you signed up on the Green Keys chat group?

>

> I did find that and am reading a

> bunch.  I have alot of terminology to

> learn and concepts to grasp.  This

> machine is fascinating, I really love

> these electromechanical devices.

Everyone on that list loves the electro-

mechanics, as well as the sound and smell

of these machines !    The list is a great

resource to learn from, and a great bunch

of guys to ask for help and info.

> The more I read the more I am sure I

> will have to get a terminal device,

> its good there are some options.  I

> had the (incorrect) assumption I

> could connect via any serial RS232

> and have that work.

Keep in mind that all Teletype machines,

excluding the "newer" ones that were for

crypto and use extensive electronics inside,

were built to run on DC current -- turned on

and off in 'binary code'...   Baudot code for

all up to Model 28.

To interface the DC current loop (60mA or 20mA)

with RS-232 you would need a suitable converter.