[GreenKeys] 28ASR Selector Magnet Driver and "Blinding"

[Robert Goff]

Hi all,
Got the 28ASR printing just fine by bypassing the SMD and tying the
selector magnets directly into the 60mA loop through the terminal block right
at the end of the LP. Quick and dirty - one of these days I'll have to
dig into the LESU and do a more permanent job (or fix the SMD!).
Thanks to everyone for your help!

With regard to blinding the selector: the 177010 spec gives
instructions for blinding with a relay on the stunt box and also
directly and permanently on the terminal block inside the LESU.

Seems like doing that would turn the machine into a send-only set with
no record of what was sent either on the keyboard or through the TD.
I just don't see why a person would ever want to do that. Like Jerry
says it makes no sense, but the instructions are there in the manual.
Is there a cryptographic reason maybe?

Thanks and 73,
de Robert W7MKA

On 6/20/21, Jerry Murphy <gfmurphy at earthlink.net> wrote:
> Take a look at paragraph 3.08 in the 177010 installation guide:
>
> http://navy-radio.com/manuals/tty/570-224-200.pdf
>
> Note:  "An external switch or relay should be provided to make the required
> connections."
>
> You are correct to assume that it makes no sense to blind the SMD without
> having a convenient way (switch or relay)
> to unblind the SMD.