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Apollo Guidance Computer Part 28: real DSKY display works again after 50 years

CuriousMarc - 2021-07-27

For the first time in about 50 years, we relight a real Apollo DSKY screen! And we can finally see the mythical glow in person. Much to our collective surprise, the screen is stupendously good - it could pass for a modern high resolution phone screen. 
We thank our sponsor *Samtec* for fabricating the NASA-spec connector pins, and of course Marcel for lending us just not one, but two of his precious displays. 

Chapters:
00:00 Intro, Apollo DSKY relight short
01:27 What's an Apollo DSKY?
02:51 Block I and Block II DSKY
07:18 DSKY Reproductions
10:19 We get our hands on two real DSKY displays
12:30 Rewiring the DSKY 
14:07 Latching relay drivers
16:39 First light with the early DSKY prototype
17:16 Checking out the NASA relay logic
22:40 Samtec pins and wire wrapping
23:57 SUCCESS! Functional flight spare DSKY!
25:55 Debugging the driver circuit
29:44 We've been hosed by CCA wires!
31:32 FIXED! Beauty shots of the working DSKY display
DSKY Relight short video: https://youtu.be/rV8NHSMH2aY

Carl's blog:
https://rescue1130.blogspot.com/search?q=DSKY

Applied Science videos on EL displays
- Electroluminescent displays: https://youtu.be/eUUupR-ongs
- DSKY display recreation: https://youtu.be/Z2o_Sp2-aBo

Apollo Guidance Computer Restoration playlist: https://youtube.com/playlist?list=PL-_93BVApb59FWrLZfdlisi_x7-Ut_-w7

Many thanks to Samtec, who re-manufactured the NASA-spec contacts: www.samtec.com
Our sponsor for PCBs: https://www.pcbway.com
Support the team on Patreon: https://www.patreon.com/curiousmarc
Buy shirts on Teespring: https://teespring.com/stores/curiousmarcs-store
Learn more on the companion site: https://www.curiousmarc.com
Contact info: https://www.youtube.com/curiousmarc/about

BADGUY 1 - 2021-07-28

I worked on the Apollo Guidance Computer software and hardware. Before that I worked on Electronic telephone exchanges. The mech charts you showed brought back old memories. Before there were sophisticated enough computers for control of equipment, we had hard wired NOR and OR gate technology to perform logical operations. Computer memories were not sophisticated enough to handle most applications (in the mid-1960's). The Apollo computer was truly unique in that it had a simple (by today's standards) core memory (called "ropes"). Those "ropes" controlled a central processor that gave instructions to the guidance and navigation system on both the Command Module and the Lunar Lander without the need for "hard wired" NOR and OR gate decision making.

MLX - 2021-07-29

Haha, the relay modules do indeed make the display sound like a telephone exchange :)

thromboid - 2021-08-03

Awesome! You're in good company - weren't Shannon and Flowers both working with telephone switching systems before basically inventing modern computers?

Owen Smith - 2021-08-12

@thromboid If you mean Tommy Flowers inventor of Colossus, yes he was a GPO engineer I believe at Dollis Hill.

Brad McBad - 2021-08-18

The first Turing complete stored-programme computer was the Manchester baby though, which used vacuum tubes instead of relay logic. Colossus was kind of a dead end as far as early computer development went.

Owen Smith - 2021-08-18

@Brad McBad But we're now into the issue of defining what constitutes a computer. Manchester uses "stored program Turning complete" because it makes them first. The US omits the "stored programme" part so it can claim EDVAC was first. Cambridge uses "stored programme general purpose computer service" ie one with input and output because that makes EDSAC first (baby had no means of output other than reading the dots on the CRTs of the Williams Tubes). And so it goes on. They were all steps on the road.

Émile Grégoire - 2021-07-28

This is the most satisfying display I have ever seen. The colour, the brightness, the clicking sound, the "animation" to get all the segments properly lit. A marvelous piece of engineering!

rtchrg440 - 2021-07-28

Absolutely outstanding Marc - really cool seeing a genuine DSKY come back to life!

cuteswan - 2021-07-28

As a little kid I thought our electroluminescent night lights were the neatest things with their eerie glow, like the older unit's bluish color. Now, despite making me think of moonlight on a summer night, they don't hold a candle to the beautiful intricacies of how this whole system operates. Thanks for the thorough video.

Graeme Davidson - 2021-07-28

The quality of engineering, ingenuity and even the fit and finish of the AGC systems is astonishing.

Poverty Spec - 2023-06-13

Especially considering that they were under immense time pressure.

Michael Carey - 2023-04-12

There is something magical about electroluminescent illumination. My late 80s Realistic radio scanner had EL backlighting for the LCD display. That soft blue/green glow was fantastic. I also recall that the first few GPS navigators released by JRC (Japan Radio Company) in the early 90s used EL backlighting as did some models of rudder angle indicators make by Tokimek (TKC) I spent almost 30 years in the marine electronics industry 🙂

nonono285 - 2023-01-07

That really is a beautiful display, there's something about it's quality and color even through video. Fantastic.

Gazdatronik - 2023-06-09

EL displays are so beautiful.
The ones in the 1966 Dodge Charger were equally crisp and wonderful
https://upload.wikimedia.org/wikipedia/commons/b/b8/66ChargerDash2.jpg

Jonathan Connell - 2022-11-15

Watching you step through those logic gates brought back great memories - thanks for this. I graduated high school in 1979 and at university we were very much still being taught to design with discrete logic gates - and people did for a long time yet to come. Micros were expensive to use unless you would write HEX code straight to the bus.The best designers were masters of the art of gate logic. I knew people who could have sketched out your entire digit control scheme in a few minutes - it was just how they thought back then. There was also a wonderful economy of design and of necessity you would find designers using all of the gates on a board - one way or another. People counted and remembered spare gates and used them later n the design cycle. Amazing in our modern world of billions of gates we treasured and used one. The sneaky, clever functionality people got out of discrete gates is amazing. My first job in the 80s - I was wiring ferrite core memory arrays not so different to the Apollo memory boards - you could hear them rattle when you read them.

youbecha64 - 2021-07-28

It just keeps getting more and more complex and innovative as you dig down into the tiniest parts!

Greg Krekelberg - 2021-07-28

Marc, you have some of the most eclectic stuff in your lab: An OS/2 box on the table and then a Marlburo box under the table. Congratulations to Carl and the crew, what a cool piece of history!

Freddy Lauwers - 2021-07-28

If they needed that much hardware to light up the display, one can see why the spacex crew dragon is so roomy. Amazing times we live in. Thank you for making these videos!

1959Berre - 2022-09-05

I was 10 years old when Armstrong and Grissom landed on the Moon. It is barely believable how sofisticated and how robust the AGC was, over 50 years ago. The dedication of those engineers and technicians was amazing.

Little Loner - 2023-02-19

My dad (in Germany) and his friend built their own cardboards rocket and almost jumped out of a height wise third story balcony to fly to the moon haha
They thankfully got caught just in time but it's amazing to me how impactful these moon landings were at the time
Wish I could've been there its hard for me to imagine how it must've been

Reality Check - 2023-07-18

Armstrong and Aldrin. Sadly Gus Grissom perished along with Ed White and Roger Chaffee in Apollo 1 fire in 1967.

Jimmy Zhao - 2022-08-25

These DSKY modules are a work of art. Those relays made such a satisfying clicking sound.

Dave Compton - 2021-07-28

I can't imagine how devastating dropping that display must have been.
Also, love that cat clock at 30:00!

CuriousMarc - 2021-07-28

This sure was annoying. But this was nothing compared to the joy of being able to demonstrate the working AGC to its creator, Eldon Hall, in person! (and I love the cat clock too!)

Paul Stubbs - 2021-07-29

@CuriousMarc I had to rewind to check out the cat

Matthew Murtha - 2021-09-19

You guys are amazing! This is satisfying on so many levels. The color, the sound and the mad skills to put it all together.

superryan94 - 2021-11-26

Thanks for the huge amount of documentation you collected, published and to some extend explain here. In my quest to build a replica of the AGC(and if time and money permit the whole cockpit) this is for me the most valuable place to find info. Hope you'll have some more of this lined up^^

vibrolax - 2021-07-28

You need to sample that relay click sound for incorporation into the microcontroller based replica DSKY's

William Manganaro - 2021-07-28

Great idea !!!

Damien Drouart - 2021-08-01

Simply use a real relay that sound similar and pulse it when necessary....

batman - 2021-08-02

they should hav jus used lcd touchscreens then ther wouldnt hav been no clicking and all.

vibrolax - 2021-08-03

@batman Well the first LCD screen wasn't produced until 1982, 20 years after the electronics for Apollo were designed. And the brightness and contrast of the early LCD's were quite poor.

Uncle Ned - 2021-08-04

Those relay clicks are truly amazing. I'd imagine they would raise some concern aboard a spacecraft which is why they were insulated, but down here they're very zen.

silver & noise - 2021-07-28

Such an amazing collection of institutional knowledge, innovative talent and skill, and technological personas in one place. Like the absolute Silicon Valley star he is, IQ points are attracted to Marc’s sphere of influence like celestial bodies to gravity. If some of the Xerox PARC guys happened to stop by that day I’m afraid all the smarts would have coalesced into a black hole nerd singularity.

Z06rcr - 2021-07-28

Great ending..not just the relays clicking.. but listen closely and you can hear the high frequency tone of the EL display change in volume as more digits light up..Very nice.

CuriousMarc - 2021-07-28

Indeed, it does that. Fine ear you have!

PJ In Europe - 2021-08-08

It's amazing that these Apollo videos keep coming. Each video lighting a different angle on the matter. I'm very much intrigued, indeed. Greetings from Belgium :)

RufftaMan - 2021-07-28

How many more episodes until a whole lunar lander is back together and ready to go? =)
Amazing work guys!

Chris D - 2021-07-28

Wonderful! That SO needs to be recreated in the same form/look as a clock or weatherstation, replete with sampled but switchable/variable clicking noises and then mass-produced and marketed appropriately as the ‘’Apollo clock’. I’d buy one 😆👍

cool_ohm - 2022-06-16

Watching the videos of yours is like living a fantasy out vicariously, keep it up. I learn so much from your hard work!

v1rotait - 2021-08-04

I'm sitting here at home by myself with a silly grin on my face saying to myself, "wow!" That is just so cool you guys got these amazing marvels of real NASA 60's relay "memory" and screen technology going. Just superb wire-wrap content for a techno geek radio technician of 28 years, who wished he could have been an astronaut. I just love this stuff, but I have no personal memory of any space flight missions as I was only 4 when Apollo 11 flew, and here in New Zealand, we had limited B&W TV, although my dad built our first B&W TV set, but I can't even remember that. I have really enjoyed this series on restoring a real AGC system! Forever grateful, David.

rpavlik1 - 2021-07-28

That is amazing to see. Way brighter and crisper than I would have expected.

Leandro laporta - 2021-07-29

Man, the clicking of the relays is absolutely gorgeous, I love that thing, the quality is amazing specially for 1960's tech OMG!

TubeTimeUS - 2021-07-28

literally the week after we filmed this, i was at work and ran into issues that turned out to be caused by CCA jumper wires. awful stuff.

MRichK - 2021-07-28

Is it just for fraud? What is the point of CCA over just Aluminum wires if the copper is so thin it make not difference? The degradation would seem to make it unusable over time.

Acme Fixer - 2021-07-28

The copper coating is to prevent the aluminum from oxidizing when the air hits it. Aluminum wire is a fire hazard when you use it in house wiring. If I find any of it, I make sure it's never used, it gets recycled.

compu85 - 2021-07-28

I always wondered why some of my jumper wires just didn't work... I've started beeping them out before I use them.

John DoDo Doe - 2021-11-21

An older version of CCA was approved for house wiring decades ago. It had thicker copper cladding, but didn't succeed commercially.

The Emerald Men Official - 2022-11-16

@MRichK Aluminum oxide (Al2O3) is downright explosive in certain conditions, and if memory serves it is often used as the fuel for SRBs as the results of its combustion are comparatively nontoxic.

An example of this is the Ariane 5’s boosters.

John Keels - 2021-07-31

It’s amazing to see how sophisticated this technology was for the time. Incredible. Still impressive engineering today.

David Johnston - 2023-02-15

Amazing! It's extremely visible and clear with the room lights on, and not too bright with the lights off. And yeah CCA speaker wire - When you strip it and twist it, the fibers fall apart in your hands and little fragments go everywhere. The thought of that carrying mains voltage is terrifying.

Ginger Ninger - 2023-06-06

This thing is beautiful, sight, sound, function, form. It's got it all.

James Halfhorse - 2022-05-02

Now I want to make one even if I have to go the LED route and use it as a smart panel in my office. I want to thank you and everyone who worked on this project. This brings history alive to me as much as seeing the first step on the moon. The engineers that made it all happen is my people. True hackers of the day that just made it work when failure wasn't an option. . Keep up all the good work you do and I will keep learning from you. Your lab is the one of dreams and I now am watching quite a bit of HP test gear on Ebay. I have an RF engineer in a box that does it all but I like the individual equipment.

Simon Strandgaard - 2022-11-13

Impressive display quality. And the clicking sounds are wonderful. Great job. Love you all.

Bik Dhaliwal - 2022-05-17

Astounding job! Marvels of ingenuity like this are truly inspiring.

FL-FLyer - 2021-07-28

Thank you for this amazing video. I have always wondered the same thing about how the original display looked because there aren't many good pictures. I can't believe people still can find components from the space program. PLEASE can you do one more video of a whole DSKY if you can find one. I would love to see how the keyboard illumination looked as well as the annunciators on the left side. THANK YOU!!!

Mike Kobb - 2021-09-21

30:55 — one of my computer hardware classes I ended up doing poorly on a lab assignment because one gate on a 74LS-series quad gate chip was bad. It absolutely never occurred to me that that was possible. Finally a TA helped debug it. I learned a great lesson from that. Fortunately, I’m old enough that crappy Chinese CCA wire wasn’t a thing yet, or that probably would have bit us as well!

Green Lint - 2021-07-28

That display is beautiful and more legible than most anything manufactured since then.

Cam Hyde - 2023-02-21

It's great being able to see the grain of the luminescent compound.. like medium ISO film but better... gorgeous display

Andy Howlett - 2021-08-02

That is a thing of beauty. Seven segment EL displays from 1965? Wow.

UKHeliBob - 2021-07-28

That relay logic is beautiful. I would have been very proud to have been the person who worked that out

C.J. - 2023-06-15

That is amazing stuff. The relay box with the EL display is so satisfying.

Artem Kashkanov Live - 2021-07-28

incredible perfect device! I love EL displays - My next video would be about powering up the whole collection of my 7-segment, 8-segment, 19-segment and etc. EL displays.
Unfortunately, all my small relays has 150V test voltage and couldn't be used here, so I selected triac optocouplers.

Keith Glaysher - 2021-07-28

Amazing work as usual Marc.

UpLateGeek - 2021-07-28

Wait, that's Tube Time? I'm a big fan of his work. He looks way younger than I expected! Considering how knowledgeable he is with vintage hardware, I envisioned a grizzled old engineer type, with grey thinning hair and multifocal lensed glasses as thick as a finger. But this one looks like a spry young whippersnapper who looks focused and attentive, clearly having wisdom beyond his years. I'm impressed.

Hobby video - 2021-07-28

awesome episode! what a cool dude marcell was for loaning his gear! EL stuff rules. I use it all the time at my job on the Denecke TS-3EL

Mike Stewart - 2021-07-28

Can confirm, Marcel is an extremely cool dude. :)

ProgramOrBeProgrammed - 2021-07-28

What a legend Ben is!

eierreiter - 2021-07-28

It's amazing how Marc supply well edited videos in such a high rate. Chapeau! Thank you very much for entertain my brain.

madmax2069 - 2021-07-30

I always loved the glow of EL (also used in night lights, and Newton message pad and other stuff).

Nicole Mellott - 2021-08-04

that relay click sound, has a very calming effect on me love it love the work you put in to bringing her back to life if i could afford one would dearly love to have a rep of the Apollo DSKY thank you for sharing

Adrian Graham - 2021-07-29

Amazing, something I never thought I'd see when I was growing up. Absolutely love the relay noise too.