[GreenKeys] 28 TD questions

Tue, 22 Jan 2002 00:17:10 -0500

Gil,

The three wire, gold plated contact assembly was designed for +/- 7V at 
1mA. It is a Tempest rated unit. The three wires connect to a polar relay 
package, and everything is shielded to minimize radiation of the signals.

But that makes it pretty simple to use it to drive an RS-232 port directly. 
Just put +6 on one side, and -6 on the other side, and connect the common 
to RD through enough resistor to make the total load about 6K ohms. I 
believe the -6 goes on the NC contact.

Bob McConnell
N2SPP

At 1/21/02 12:50 PM -0700, gil smith wrote:
>Hi Jack:
>
>At 01:58 PM 1/21/02 -0500, you wrote:
> >...Before you get too worried about
> >the pins...look very carefully to make sure the pins
> >have not slipped below the plate and/or they're not blocked
> >by dirt in the slots. Kinda unusual for them to be
> >broken.
>
>Hee-hee-hee-hee (insert big smile here)!  After a closer inspection of the
>sense pin area, I found that the pins had indeed simply been pushed down
>and off to the side of their guide slots.  I was able to easily pop them
>back into position, and things seem to cycle fine now.  That was nice to find!
>
>
> >The LXD runs on a normal 130VDC loop and the control solenoid
> >should work on 110VAC...
> >The rear connections should have the tape out/tape jam
> >switch, the control solenoid and the mark (space)
> >contacts. Easiest way to determine the mark/space
> >contacts it to hook up a VOM and run a tape through (once
> >you fix the pins, of course). I'm guessing that the three-pin
> >connector is the signal generator's mark/space/common
> >connections. They come from the small closed metal
> >box in the machine.
>
>Yes, there is a metal can (that says "do not oil") which is the origin of
>the cable that terminates in the 3-pin circular connector.  Hmm,
>mark/space/common, so there is a separate switch contact for each?  I was
>expecting a a simple open/close contact for keying the loop.  How does the
>mark/space scheme usually hook up?  And how would you determine the
>mark/space contact connections with a meter (or scope)?  Are these contacts
>good to at least 150VDC?
>
>BTW, pics are at (click on them to enlarge):
>http://www.vauxelectronics.com/gil/tty/gil-M28-TD.htm
>
>
> >I don't have any military wiring
> >diagrams, but the presence of the two terminal strips seems
> >to indicate it's not overly different from a standard
> >Teletype TD.
>
>The lower terminal strip is just for 115VAC, but the upper terminal strip has:
>1 - Wht     (cable-1)
>2 - Blk     (cable-1)
>3 - Shield? (cable-1)
>4 - Shield? (cable-2)
>5 - Wht     (cable-2)
>6 - n/c
>7 - n/c
>8 - Blk     (cable-2)
>9 - n/c
>
>These cables go to the delta connector under the LXD.  I can trace these
>connections out, but it would be handy if someone has a wiring diagram for
>the LXD assembly and its delta connector.
>
>
> >I'd recommend putting a resistor in series with
> >the control solenoid just to be safe. There's always the
> >possibility that it's a 48V coil.
>
>Anyone know what coil resistance would be for the 48V and 115V coils?
>Else, I can try 48V first (dc?) to see if it pulls in.
>
>
>And what about some lubrication advice?
>
>
>Thanks Jack!
>
>gil
>
>
> >Jack WA2HWJ
> >-----Original Message-----
> >From: [email protected]
> >[mailto:[email protected]]On Behalf Of gil smith
> >Sent: Monday, January 21, 2002 12:11 PM
> >To: [email protected]
> >Subject: [GreenKeys] 28 TD questions
> >
> >
> >Hi folks:
> >
> >I have an M28 TD standalone unit (TT-603/UG) that I'd like to get working.
> >I connected AC and the motor turns the mechanism just fine.  When I use a
> >plastic rod to push the "run" solenoid gizmo, it feeds paper tape and I can
> >see the sense pins coming out etc.  I have two problems though:
> >
> >First, I only see three of the five sense pins come up, so something is
> >broken inside.  I have a spare LXD37 reader mechanism (serial 15!) that
> >looks in decent shape, but I can't just swap the LXD out since the
> >driven-shaft/gear portion is different.  I think I can either swap the
> >driven-shaft parts, or the sense pins parts, whichever is easier.  Anyone
> >have words of wisdom on dismantle and reassembly?
> >
> >Second, I have no documentation, so I am curious about the wiring.  There
> >are two 9-position terminal strips inside.  The lower strip has AC
> >connections for the line cord, internal power switch, and chassis ground --
> >this was easy enough to figure out.  The upper terminal strip has
> >connections to what appears to be two shielded-twisted-pair wires, with all
> >six connections available.  These wires go to a delta connector underneath
> >the LXD reader mechanism.  I presume one of these cables provides a
> >low-voltage supply for the run solenoid, and the other one looks like it
> >goes to a switch. Then there is what looks like another
> >shielded-twisted-pair cable that is terminated in a 3-pin circular
> >(mil-type) connector -- I presume this provides the data switch contacts
> >for the loop.  I can likely figure this other stuff out as well, but if
> >someone knows connection information, I'd appreciate it.  Specifically,
> >what voltage does the run solenoid need, and what loop voltage are the data
> >contacts rated for?
> >
> >thanks,
> >
> >gil
> >
>
>
>;-----------------------------------------------------------
>;  vaux electronics, inc.             480-354-5556
>;  http://www.vauxelectronics.com     (fax: 480-354-5558)
>;-----------------------------------------------------------
>_______________________________________________
>GreenKeys mailing list
>[email protected]
>http://mailman.qth.net/mailman/listinfo/greenkeys