Burroughs Panaplex II clock display...

[Nick]

Nice Burroughs Panaplex clock display, Kr85 (in theory). Very thick glass and ceramic. Flexible cable connector between lower part of display and ceramic - gap is maybe 0.25mm - gold plated tabs on the ceramic.

Seven-Segment Gas-Discharge-Plasma Display - PANAPLEX,7 Seg,Clock
Package Style (Basic)=1-Edge no
Color=Orange
Number of Digits=4
Character Height (mm)=18
Vsup Nom.(V) Supply Voltage=200
Iseg (A) Segment Forward Cur.=1.2m
t(resp) Max.(s) Response Time=250u
Lv Typ.(fL) Luminance=45
@Vsup (V) TEST CONDITION=200
Status=Discontinued
Package=1-Edge no

Nick

[SWISSNIXIE - Jonathan F.]

Nice!

There is also a 6 digit version of this, but has no white backside.  Saw it on ebay a few days ago.

 

[ZY]

What does the Kr85 stand for? I see it on one of my displays too.

[JohnK]

Try this...

https://en.wikipedia.org/wiki/Krypton-85

 

You might be surprised at the number of tubes that over the years have had 'radioactive' contents. Many gas discharge devices had it added to regularise the characteristics for light/dark operation (trigger tubes and regulators) or their trigger parameters (eg TR cells).

 

Some of the WWII era radar devices [and later ones with warnings displayed] have truly dangerous types and quantities of 'radiation'. There are web lists of tube types.

 

John K

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[ZY]

Ah I see. That has me wondering what a nixie tube made completely out of uranium glass would look like.

[John Rehwinkel]

> Ah I see. That has me wondering what a nixie tube made completely out of uranium glass would look like.

It would have a slight greenish-yellow tint, and would fluoresce brightly in UV. I wonder how much UV a nixie discharge creates.

- John

[taylorjpt]

The Kr85 is a gas in the tube that decomposes by beta decay to supply an ionization potential to allow the display discharge to start quickly.  The beta particles can't penetrate glass or ceramic of the envelope but when broken open you can read it with a Geiger counter.

The segment cathode contacts on the base are usually sintered silver; never seen gold plated units before.  The anode contacts are transparent ITO (Indium Tin Oxide) on the face plate glass.

jt

[gregebert]

Kr85 has a 10-year half-life, so displays manufactured in the 1980's will have about 10% of the radioactivity they once had.

I recall reading somewhere that Kr85 was optional in displays; generally intended for low or zero ambient-lighting conditions. So even if your display's radioactivity has withered-away it is still operable.

[Nick]

Just noticed that these don't seem to have an obvious anode connection - has anyone powered one up, and if so, what sort of connection did you use?

You can see the anode (transparent-ish metal film over the face of each digit), but no obvious way of making a connection to it, though the metal film does seem to extend into the connection area for the cathodes. I've tried taking a photo of it, but being transparent, it doesn't show up very well !

Nick

[gregebert]

Since it's multiplexed, there should be 4 or 5 anodes (and obviously 7 segments) depending upon how the colon, AM, and PM connections are made. I counted 18 pins total, so it's very possible there are individual cathodes for A,M,P,M, and each of the 2 dots in the colon. This is what was done in the SP-151 display I have in my wristwatch.

BTW, the SP-151 is probably an earlier-generation display because it has visible contacts that appear to touch a thin film deposited on the inner surface of the frontal glass. I'm sure the pinout is similar to your Panaplex.

As far as identifying the anodes, you will eventually find them by trial-and-error. Just be careful to limit the current to very low values, maybe 100-200uA. Remember there's no need to apply full-rated current (ie, full brightness); all you need is just enough current to see a faint glow to ID the pins. You will inevitably apply ~180V across 2 adjacent segments (which have almost no spacing), so a very high electric field will be present which could damage the device if done for extended time. You'll probably see a blue dot.

[Nick]

I've built a large number of Panaplex-based clocks over the years, so am well used to them. Just checked - still got several 100 displays, including a lot of SP101s and for some reason, trays of SP336s as well a a few "exotics".

These CM (Custom Module) displays have already been probed - the hh:mm:ss variant has duplicate segment pins for the left-most digit - both displays were reluctant to light fully at first (as are a lot of Panaplex displays which have been in storage for a long time), but a bit of persuading and they're there now.

Nick

[Stephen]

I have one of the four digit versions as well as one of the six digit. They are screaming to be made into clocks!

Does anyone know of a source for the connectors for these, or ideas on how to make one? I've scoured the 'net and came up empty.

So far, the best idea I have is to cut some phosphor bronze strips, fold over the ends to make a sort of spring, and solder them onto a .100" header.

--Stephen

[taylorjpt]

I have a pile (~1K) 11 digit calculator displays and eventually settled on a 0.5mm thick double sided translator board installed with conductive epoxy. The connection now becomes a simple DIP header: http://www.ebay.com/itm/140729423185

I remember having a bag of the clips back in the '80s and thinking... "When would I ever need these?".

[Stephen]

On Sunday, August 21, 2016 at 6:02:53 AM UTC-4, taylorjpt wrote:

I have a pile (~1K) 11 digit calculator displays and eventually settled on a 0.5mm thick double sided translator board installed with conductive epoxy.  The connection now becomes a simple DIP header: http://www.ebay.com/itm/140729423185

I remember having a bag of the clips back in the '80s and thinking... "When would I ever need these?".

I saw these on eBay, and figured the PCB was attached by the calculator manufacturer. I'll have to get one.

When I think about using conductive epoxy, I worry about shorts between conductors. How do you avoid that?

Any chance you'd put some of the boards up for sale? No idea where I'd get .020" thick boards made in small quantities...

Yeah, I had a small collection of Panaplex displays from Radio Shack display assortments that I threw in the trash, thinking there was no way for me to ever use them... And to think of some of the junk that did get saved!