Huh - the Navy manual does not show a loop supply, but the referenced 2852WD does (and says LESU5/110)
I dunno - maybe they got confused back in 1953....
Nick England K4NYW
www.navy-radio.com


On Mon, Jul 14, 2025 at 3:03 PM Nick England <navy.radio@gmail.com> wrote:
Seeing the cloth-covered wires made me think it was an early model. I have a TT-47A with a LESU that looks very similar except no loop supply which looks like a ham add-on.
The TT-47A LESU is Navy model SB-154A. Teletype model LESU5/103
Manual is at
https://www.navy-radio.com/manuals/tty/tt47a-91713-5207.pdf

Wiring diagrams 2852WD and 2853WD are in 573-100-400
https://www.navy-radio.com/manuals/tty/573-100-400.pdf

Nick England K4NYW
www.navy-radio.com


On Mon, Jul 14, 2025 at 1:59 PM Duncan Brown <duncanancy@earthlink.net> wrote:
I'm checking out a M28KSR that looks like it has had some major rewiring done to it.

All the jumpers that are normally on terminals 4-14 of the cabinet terminal blocks have been removed.  There were two, 4 conductor, external cables connected to the cabinet terminal block, all unterminated, except for a 2k power resistor (loop current limiter) connected across  C10-C11.

I see no designator on the LESU and the color codes of the cable from the LESU to to c5 - c14 do not match the colors I see on 2874WD (or any others).  The LESU has what looks like a Line Shunt Relay, a 120VDC power supply (with monitor jack), a Motor-Stop relay and an 120VAC input panel ( lamp switch & fuses). See picture enclosed.

Can anyone identify this LESU?

I tried to remove the LESU by removing the big screws.  The LESU was loose, but would not come out, apparently because of the front panel power switch extension mechanism.  I expected it to disengage when I lifted up the LESU, but it did not.  Is there something in the switch extension mechanism that has to be removed/released?


Thanks,

Duncan
K2OEQ

 


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