1 Mar
2008
1 Mar
'08
1:40 a.m.
--------Original Messages:
Date: Fri, 29 Feb 2008 23:22:16 -0800
From: Brent Hilpert <hilpert at cs.ubc.ca>
Subject: Re: seven segment display history
To: General at priv-edmwaa04.telusplanet.net,
"Discussion at priv-edmwaa04.telusplanet.net":On-Topic and Off-Topic
Posts <cctalk at classiccmp.org>
Message-ID: <47C90428.4A52403B at cs.ubc.ca>
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Ethan Dicks wrote:
I have something like that with me here in my bag-o-parts... approx 20mm
by 30mm, with a 2mm-thick body made of a rough, dark ceramic, with a 1mm
thick glass top. It's a 2.5 digit display with + and -. All the leads
come through the back of the package in what appears to be a straight-
through fashion (making it easy to figure out how to hook it up).
There is a vendor and part number etched on the face: Sperry SP-738.
I've never tried to hook it up to anything, and have no idea what
voltages it might want. It's a shame it's only 2.5 digits; if it
were 3.5 digits, it might make an interesting 12-hour clock face.
Not sure what I'd need to do that swings from -199 to +199 off the
top of my head.
Temperature?
Your description sounds like the Sperry/Beckman gas-discharge displays, e.g.:
http://www.tube-tester.com/sites/nixie/trade08-panaplex.htm
I think your part number is in there.
Can be cascaded with more digits, or a lot of early DVMs were only 2.5 digits.
----------------Reply:
A little tricky to interface because of the high voltage, keep-alive anodes, etc.
I may have some of the driver chips though if you're serious.
mike
1 Mar
1 Mar
4:18 a.m.
On Sat, Mar 01, 2008 at 04:40:02AM -0500, M H Stein wrote:
Ethan Dicks wrote:
Yeah... I read the specs. I'm know about nixies and plain neon tubes,
etc., but I don't know anything about "keep-alive anodes".
There is a vendor and part number etched on the
face: Sperry SP-738.
A little tricky to interface because of the high voltage, keep-alive
anodes, etc. I may have some of the driver chips though if
you're serious.
I would love to make this do something useful. The display was
free (I got it in a pile of parts from a friend who retired and
left the State), but I've always wanted to do something interesting
with it. Perhaps an AVR-controlled, Dallas 1-wire thermometer
display?
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 1-Mar-2008 at 12:10 Z
South Pole Station
PSC 468 Box 400 Temp -58.7 F (-50.4 C) Windchill -87.0 F (-66.1 C)
APO AP 96598 Wind 7.7 kts Grid 133 Barometer 689.0 mb (10291 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
8:54 p.m.
Ethan Dicks wrote:
On Sat, Mar 01, 2008 at 04:40:02AM -0500, M H Stein wrote:
Forgot before, Heathkit used those Sperry/Beckman displays in their 70's-era
digital doodads like clocks, indoor-outdoor thermometers, weather monitors,
tachs, & c., might be a place to look for schematics for examples of real-world use.
Ethan Dicks wrote:
Yeah... I read the specs. I'm know about nixies and plain neon tubes,
etc., but I don't know anything about "keep-alive anodes".
There is a vendor and part number etched on the
face: Sperry SP-738.
A little tricky to interface because of the high voltage, keep-alive
anodes, etc. I may have some of the driver chips though if
you're serious.
I would love to make this do something useful. The display was
free (I got it in a pile of parts from a friend who retired and
left the State), but I've always wanted to do something interesting
with it. Perhaps an AVR-controlled, Dallas 1-wire thermometer
display?
11:09 p.m.
On Sat, Mar 01, 2008 at 08:54:10PM -0800, Brent Hilpert wrote:
Ethan Dicks wrote:
Oh, yeah. I even have one of those 6-digit Heathkit clocks. Still, the
trick with those is that some of the Sperry/Beckman displays have keep-
alive-anodes, and some do not. From the one link that was recently
posted, it's clear that there was a large variety of displays made back
in the day, and you could select a display for your requirements (especially
how many primary anodes for multiplexing).
In this case, I have a particular display, one of the more complex ones,
looking for an application; not the other way around.
Still... I'll have to go digging for some Heathkit schematics anyway.
ISTR that my clock is a little funky - either the displays are wearing
out, or I have something going off in the driver circuit. I _think_ the
symptom was that as the clock warmed up, segments that shouldn't be lit
started to fade in, then the clock went to 88:88:88.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 2-Mar-2008 at 06:59 Z
South Pole Station
PSC 468 Box 400 Temp -54.9 F (-48.3 C) Windchill -89.2 F (-67.3 C)
APO AP 96598 Wind 12.5 kts Grid 13 Barometer 688.3 mb (10317 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
> > There is a vendor and part number
etched on the face: Sperry SP-738.
Forgot before, Heathkit used those Sperry/Beckman displays in their 70's-era
digital doodads like clocks, indoor-outdoor thermometers, weather monitors,
tachs, & c., might be a place to look for schematics for examples of real-world use.
3 Mar
3 Mar
1:21 p.m.
Ethan Dicks wrote:
On Sat, Mar 01, 2008 at 08:54:10PM -0800, Brent Hilpert wrote:
No, I didn't mean to suggest that you would want to re-implement one of the
Heathkit designs/apps, just that the Heath schematics might be available and
might provide some circuit examples/hints of biasing techniques, drivers, & c.
(not always included on spec sheets).
e.g.: As it turns out, I have the schematic for the GC-1092 clock here (don't
have the clock, just the schematic, which has been hanging around in my files
since the 70's). It uses SP-352 displays, and shows the keep-alive cathode and
supply, etc.
Don't know why that web page refers to the Sperry/Beckman displays as Panaplex,
my understanding was Panaplex was a Burroughs trade name for their 7-seg
gas-discharge displays.
Ethan Dicks wrote:
Oh, yeah. I even have one of those 6-digit Heathkit clocks. Still, the
trick with those is that some of the Sperry/Beckman displays have keep-
alive-anodes, and some do not. From the one link that was recently
posted, it's clear that there was a large variety of displays made back
in the day, and you could select a display for your requirements (especially
how many primary anodes for multiplexing).
In this case, I have a particular display, one of the more complex ones,
looking for an application; not the other way around. > > There is a vendor and part number
etched on the face: Sperry SP-738.
Forgot before, Heathkit used those Sperry/Beckman displays in their 70's-era
digital doodads like clocks, indoor-outdoor thermometers, weather monitors,
tachs, & c., might be a place to look for schematics for examples of real-world use.
12:15 p.m.
M H Stein wrote:
--------Original Messages:
Date: Fri, 29 Feb 2008 23:22:16 -0800
From: Brent Hilpert <hilpert at cs.ubc.ca>
Subject: Re: seven segment display history
To: General at priv-edmwaa04.telusplanet.net,
"Discussion at priv-edmwaa04.telusplanet.net":On-Topic and Off-Topic
Posts <cctalk at classiccmp.org>
Message-ID: <47C90428.4A52403B at cs.ubc.ca>
Content-Type: text/plain; charset=us-ascii
Ethan Dicks wrote:
anodes, >
etc.
I have something like that with me here in my
bag-o-parts... approx 20mm
by 30mm, with a 2mm-thick body made of a rough, dark ceramic, with a 1mm
thick glass top. It's a 2.5 digit display with + and -. All the leads
come through the back of the package in what appears to be a straight-
through fashion (making it easy to figure out how to hook it up).
Your description sounds like the Sperry/Beckman gas-discharge displays, e.g.:
http://www.tube-tester.com/sites/nixie/trade08-panaplex.htm
I think your part number is in there.
----------------Reply:
A little tricky to interface because of the high voltage, keep-alive I may have some of the driver chips though if
you're serious.
I actually have a bunch of those too, culled from the guts of an old gas pump.
I remember rigging up something with a bunch of transistors a couple of years
ago just to interface them to some LS-TTL and try them. Nice glow to them.
In the context of Apollo displays, I'd figured them to be a lot later - mid
'70s or so. (the biggest ones I have are about 3/4" for the actual digits too,
a lot smaller than the mocked-up ones on the Apollo computer I saw)
cheers
Jules
6139
days inactive
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dm561＠torfree.net -
ethan.dicks＠usap.gov -
hilpert＠cs.ubc.ca -
jules.richardson99＠gmail.com