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

[Robert Goff]

Hi Jerry et al,

I think my ASR is a bit of a "depot dog" : there are no military tags
on the cabinet, in fact there is a big Western Union sticker with SF
phone numbers, but it does have a LESU 111.  I've been following the
wiring diagram for that LESU which I found on Nick's site (Thanks
Nick!) It does show the SMD in the signal line.

I think I'm just going to have to face up to pulling the LESU out so I
can either repair the SMD or wire it up to drive the selector
directly.

Thanks everyone for the good advice!
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.
>
> What version M28 ASR do you have?  If it is a Navy machine, there should be
> a label on the cabinet right below the
> keyboard hood.  The UGC-6K had a selector magnet driver to operate the page
> printer.  There was no external blinding
> arrangement for the page printer.  The UGC-6K had an LESU 111 in it.  The
> schematic and actual can be found at:
>
> http://navy-radio.com/manuals/tty/wd/wd-tty-7015-7016.pdf
>
> Good luck with your project.
> Jerry Murphy
>