[GreenKeys] Fwd: Creed 444

[Alf Fisher]

Steve,
The attached circuit should do what you need.
Its usual to use plus and minus 80 volts.  It will probably work with 48
volts but the end of line neon probably wont light up.
The operating current for a double current circuit is 20 mA so you will
need a resistor of about 1.8K ohm 2 watt but you might need to
experiment with that to get near enough to 20 mA.
The 100 ohm resistor bulbs are the traditional way to protect the
supplies in the event of a short circuit appearing across the Mark and
Space contacts which are very close together.   There is probably a
modern thermistor device that would do the same job as these bulbs but
I'll have to leave that for someone with greater knowledge than me!

Alf
G3WSD

On 20/08/2026 19:41, stephen.lyne1--- via GreenKeys wrote:
>
I wish to run my Creed 444 as a stand alone demo but I need to know
the pin connections on the 50 way D-sub plug to allow the machine to
function, any help would be appreciated.
>
> Steve
> ______________________________________________________________
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