Sperry SP-425-08 Display - Datasheet?

Anders Nelson anders.k.nelson at gmail.com
Wed Jan 1 20:14:43 CST 2020

Wow, thanks for all the info! I'd love to see examples of driving circuitry
if it's not too much trouble. I've made PCBs and such before so aside from
potentially jolting myself I'm up to the challenge.

Anything I produce (code, schematics/PCBs) will be posted to my blog as
open-source material.

Thanks again,


On Wed, Jan 1, 2020, 8:34 PM Brent Hilpert via cctalk <cctalk at classiccmp.org>

> On 2020-Jan-01, at 2:42 PM, Anders Nelson via cctalk wrote:
> > I snagged one of these Nixie-like displays (from a calculator I assume)
> and
> > I'd like to light it up. Does anyone know where I might find the
> datasheet
> > for it? Google hasn't turned up anything.
> >
> > https://www.ebay.com/itm/264110638970
> >
> > Any help is appreciated!
> 7-segment multiplexed multi-digit gas-discharge display.
> Those Sperry types weren't very prevalent, I'm not surprised you haven't
> found a datasheet.
> I'm being a little presumptuous in specifying gas-disharge, it certainly
> appears to be, but the ebay pics are a little small.
> There was another series of GD displays from Sperry, and another from
> Beckman, which were more prevalent.
> Assuming it is GD:
> I have an example of one that appears to be of similar construction to
> yours in this calculator:
>         http://madrona.ca/e/eec/calcs/SanyoICC83.html
> Given yours says made in Japan, I wonder if they be from the same OEM.
> I can send the schematic if you wish, for an example of drive circuitry.
> It needs a little reformatting and conversion to pdf first, so let me know
> if interested.
> I have other calculators and schematics using the Beckman displays
> (7-segment, multiplexed, multi-digit, gas-discharge).
> They could also be comparitive examples for drive circuitry.
> Multiplexed gas discharge displays could be a little finicky to drive, to
> keep down anomylous ghosting and partial ignition.
> In the absence of a datasheet, your first task would be to distinguish the
> digit anodes from the segment cathodes.
> You might be able to do it visually by looking at the internal
> construction.
> Otherwise experimentation with two probes connected to a 150-200V power
> supply with a series limiting resistor of 200K or maybe even higher to
> start with.

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