I found a document that says LXD7 was also used in the AN/FGC-56 and FGC-58 model 28ASR. I found a parts manual on line (TM11-5815-263-34P) but no schematic yet. If these were Navy units I'd know where to look, but these were Army M28 units (weird!). Maybe you know what manual number to look for that might have a schematic.

Parts pages for the LXD7 transmitter are attached.

So does the contact wiggler go back and forth when you are reading tape? If it ain't wiggling, the contacts ain't gonna do anything.

Nick England K4NYW
www.navy-radio.com

On Fri, Jul 29, 2022 at 6:05 AM Nick England <navy.radio@gmail.com> wrote:

Teletype made hundreds of variants of basic assemblies such as the LXD. So how do you tell the difference between an LXD6 and LXD7 for example?

The Analysis Chart !

https://www.navy-radio.com/manuals-ttycorp.htm#analysis

Fortunately Jim Haynes rescued a few of these rare beasts. Unfortunately the LXD one is among the missing. 

So your best chance is finding a wiring diagram that includes LXD7 along with other variants. It might include a note about the transmitter box. Sometimes the parts manual will include differences. 

More later today. 

Nick

On Thu, Jul 28, 2022 at 10:16 PM Duncan Brown <duncanancy@earthlink.net> wrote:

Having been assured that the motor in this M28 tape unit is correct
(even though the leads were short), I've progressed to being able to
move tape through the machine and confirm that the  "tight tape" and
"tape out" functions are working.

But no signal out. I traced the signal back to the connector that the
LXD7 plugs into, so the next step was to check the contacts in the
Signal Contact Box. I removed the nut on the top of the box and the
cover is loose, but I can't get  the cover off due to interference with
an arm of the Front Plate.

How do I get the top off the Contact Box to  check the contacts?

I see there are a variety of contact boxes used with the LXD tape
reader.  How do I know which one was used with the LXD7?

Thanks,

Duncan
K2OEQ