[GreenKeys] Run teletype model 15/19 keyboard and printer on different circuits?

[Windows XD]

I see, I'll keep that in mind if 5v does not work

Will that still happen with a solid state relay? I thought those didn't use
magnets and instead used a photocoupler or something similar.

On Wed, Sep 17, 2025, 9:36 AM Mike Douglas <deramp5113 at yahoo.com> wrote:

> I have found I had to go to 12v-15v across the keyboard to get reliable
> operation across a variety of machines. 5v may be OK for a given keyboard
> if its contacts are in good shape and show low resistance (< 1 ohm) when
> closed.
>
> Directly running a relay coil with your keyboard isn't going to totally
> solve your arcing problem since the relay coil voltage will also build to
> the point it discharges via an arc across the keyboard contacts whenever a
> switch opens. There will be less energy stored in the relay coil than in a
> selector magnet coil, but you'll still get an arc. If you build a snubber
> for the relay coil, you have to be sure it still allows the relay to switch
> fast enough for reliable 45.5 baud operation.
>
> Mike D
>
> On Tuesday, September 16, 2025 at 08:44:09 PM CDT, Windows XD <
> antech6586856 at gmail.com> wrote:
>
>
> Dear all,
>
> I was working on the teletype when I had an idea. I have already picked up
> a solid state relay capable of switching faster than the 45.45 baud needed
> for the teletype for something else I'm working on with the teletype, and I
> was wondering if it would be possible to run the keyboard on a 5vdc circuit
> wired to said solid state relay and have the keyboard run on 5vdc and the
> selector magnets at 120vdc. I can't think of any obvious problems with
> running the keyboard at this lower voltage, but I'd like to be sure.
>
> I'm not sure I explained it super great so I've attached a schematic,
> although I'm not sure if it's any better than my explanation.
>
> P.S. My keyboard has arcing problems with the contacts, will this
> modification coincidentally also fix that?
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