Apollo Saturn V computer logic reverse engineered - with working model. - Page 1
Forum section: electronics / general

author: Frantone
author_rank: Regular Contributor
timestamp: February 08, 2013, 09:08:17 pm
content: For the full article about this with photos go to my Design and Engineering page:http://www.frantone.com/designwritings/design_writings.html#LVDCcode

author: dda
author_rank: Contributor
timestamp: February 08, 2013, 09:27:48 pm
content: Noob question. I havent seen transistors arranged in that way before, inputs on the emitters, and the collectors connected to the base of the third... What is actually happening here? Im having trouble following it.

author: Frantone
author_rank: Regular Contributor
timestamp: February 08, 2013, 09:34:42 pm
content: Quote from: dda on February 08, 2013, 09:27:48 pmAh - you have to think about the direction of current and the way transistors switch. These DTL and TTL circuits work on the idea that you ground the emitter/cathode to allow current flow and otherwise the bases are pulled high. Each gate assumes there is a high bit there unless it is told otherwise by a low (ground) state. It seems bass-ackwards but this is how it was done.

author: JackOfVA
author_rank: Unknown
timestamp: February 08, 2013, 10:09:28 pm
content: If my research is correct, the first TTL devices to hit the general market were by TI and it was 1962, a year or so after TTL was invented. If so, TTL was a known, but new, technology when the IBM 360 hit the market. Considering how long it must have taken for IBM to bring the 360 to market (Fred Brooks book, "The Mythical Man Month" featured his experience developing the initial 360 operating system as I recall) TTL was likely not available when the 360 was originally designed.DTL was a few years earlier - I recall seeing DTL surface mount flatpacks made by (I think) Westinghouse around 1966 when at University studying electrical engineering. At that time, all my home brewing of logic was with RTL, though, as it was considerably more available and affordable.

author: Frantone
author_rank: Regular Contributor
timestamp: February 08, 2013, 11:00:45 pm
content: Quote from: JackOfVA on February 08, 2013, 10:09:28 pmI have read that as well, though I have found no real-world application of TTL that early. I do think that the IBM LVDC was the first time a complete system was built on TTL. I could be wrong, but I have found nothing this involved made from TTL that early.

author: w2aew
author_rank: Super Contributor
timestamp: February 08, 2013, 11:13:38 pm
content: Another great video, Fran! That chip mounting technology looks like the predecessor to C4 (Controlled Collapse Chip Connection), basically a micro-version of BGA.

author: Psi
author_rank: Super Contributor
timestamp: February 08, 2013, 11:21:34 pm
content: Any idea how many of those boards made up the entire CPU?

author: Frantone
author_rank: Regular Contributor
timestamp: February 08, 2013, 11:26:30 pm
content: Quote from: Psi on February 08, 2013, 11:21:34 pmI only have one board, but photos available online of semi-filled LVDC modules show many - and the system was triple redundant, with three computers working in parallel, and a majority vote system for final decision making of attitude and control.

author: JackOfVA
author_rank: Unknown
timestamp: February 09, 2013, 12:20:17 am
content: The Computer History museum says:Patented by James Buie of Pacific Semiconductor in 1961, TTL (Transistor Transistor Logic) emerged as the most popular logic configuration of the next two decades. Unaware of Buie's work but inspired by an "all transistor" logic circuit described by Ruegg and Beeson of Fairchild, Thomas Longo led the design of the first TTL family, Sylvania Universal High-level Logic (SUHL) in 1963. Encouraged by SUHL's success in winning a high-profile Hughes military design (the Phoenix missile), TI introduced the competing SN5400 Series TTL family the following year. The company announced the SN7400 Series in low cost plastic packages for industrial customers in 1966 and quickly gained a greater than 50% share of the logic market.http://www.computerhistory.org/semiconductor/timeline/1963-TTL.htmlI recall SUHL after this jogged my memory.

author: Raff
author_rank: Regular Contributor
timestamp: February 10, 2013, 01:50:09 am
content: Wow! without a doubt very cool! Thanks for the videos, i have subscribed to your channel.

author: Frantone
author_rank: Regular Contributor
timestamp: February 10, 2013, 02:28:40 am
content: It works.....I will make the video about how to Build Your Own LVDC Logic Devices with modern surface mount components next week. Reflow your way into the Apollo Program!

author: dda
author_rank: Contributor
timestamp: February 10, 2013, 02:30:04 am
content: Quote from: Frantone on February 08, 2013, 09:34:42 pmAh, cheers. I did some googlin', and thinking of that transistor as a couple of diodes makes it easier for me to visualise.I also looked at the NOT gate on your website fran, my next question is about the two diodes next to the output of the not gate... What would be the effect of omitting them?

author: Unknown
author_rank: Unknown
timestamp: February 10, 2013, 03:06:25 am
content: Fran you've got me reading about LVDS and ECL ever since you posted the video. Thanks!

author: Raff
author_rank: Regular Contributor
timestamp: February 10, 2013, 03:09:17 am
content: Well there goes Sunday

author: Frantone
author_rank: Regular Contributor
timestamp: February 10, 2013, 04:49:26 am
content: Quote from: dda on February 10, 2013, 02:30:04 amHmmm... Good question - Dual diodes is overkill and the lower NPN transistor is an adequate emitter follower in itself, so I would think it would be stable without the diodes. I do think though that having at least the one diode between the upper emitter and the output would help a lot with balancing the output impedance when the NOT gate output goes high under load.

author: smashedProton
author_rank: Frequent Contributor
timestamp: February 10, 2013, 05:06:47 am
content: Congratulations fran! Not only for an excellent thread, but you have posted one of the few on topic threads

author: Frantone
author_rank: Regular Contributor
timestamp: February 15, 2013, 05:31:49 am
content: LVDC-NAND Dual PCB Prototype -Demonstration of the production prototype of my LVDC NAND gate package, with dual surface mount PCBs.

author: Frantone
author_rank: Regular Contributor
timestamp: February 17, 2013, 05:09:07 am
content: Final specs and artwork for the Do-It-Yourself LVDC project are here:http://www.frantone.com/designwritings/design_writings.html#LVDCbuildGood luck, and have fun! O0

author: seth13699
author_rank: Contributor
timestamp: March 08, 2013, 02:13:10 pm
content: Hi guys and gals,First of all I've been lurking Dave's and Mike's (mikeselectricstuff) youtube channels (and this forum) for some time now and I'd like to take advantage of this opportunity to thank them both for sharing their accumulated knowledge over the years with all of us. Thanks guys!!!I just found out about Fran's channel though and I was immediately hooked by the LVDC videos. That was awesome Fran!!!I am a fellow Apollo era hardware buff and I too acknowledge the importance of these relics and the tremendous impact they had in the industry over the years (albeit largely forgotten for various reasons as Fran pointed out).Now to the point (after this brief intro). I own, among other things, 2 page assemblies. One from a LVDC "flight ready" spare, and another one from a cannibalized (literally!!!) test rig.The first one is on display in my collection and it's in pristine condition (like new!!!). Here are a few pics:The other one though had a tough lifeI was told it spent years on a junkyard exposed to the elements, and that left it's marks as you can see below:I was planning to "destructively" reverse-engineer that one, popping the lids off some of the flat packs or just see if the transistors still work after all this years. Unfortunately I simply don't have the time (or access to fancy X-Ray machines).I'm willing to donate that PCB to either Dave, Mike or Fran in exchange of a video (or a series of videos) dedicated to this extraordinary piece of Space Age history.Any volunteers?P.S.: I'd prefer an in depth analysis (even if that meant de-soldering or "breaking" components) but you can choose to preserve it as is (or restore it to some extent) instead. The choice is in the hands of the chosen one!!!For SCIENCE!!!

author: bradleytron
author_rank: Regular Contributor
timestamp: March 08, 2013, 03:04:22 pm
content: Quote from: seth13699 on March 08, 2013, 02:13:10 pmHow about your friendly local dentist, might they allow you to use their x-ray machine?

author: seth13699
author_rank: Contributor
timestamp: March 08, 2013, 04:17:41 pm
content: I tried...no joyI guess she (my dentist) wasn't convinced about the value of the artifact and the importance of X-Raying it.Bummer...

author: Frantone
author_rank: Regular Contributor
timestamp: March 08, 2013, 06:53:23 pm
content: Quote from: seth13699 on March 08, 2013, 02:13:10 pmYYYYEEEEESSSS!!!!!! I WILL TAKE IT!Email me through my websitewww.frantone.comand I will arrange shipping. The exposed junkyard board would be ideal for surgery - I would like to take off some of the devices to check the values and such for the gates.Awesome!O0

author: seth13699
author_rank: Contributor
timestamp: March 08, 2013, 07:59:33 pm
content: Quote from: Frantone on March 08, 2013, 06:53:23 pmYou have PM...

author: BartManInNZ
author_rank: Contributor
timestamp: March 11, 2013, 03:00:20 am
content: This thread along with your site Frantone has given me much joy - the amount of awesome is too much!Keep up the great work!

author: mwtheobald
author_rank: Newbie
timestamp: March 11, 2013, 01:30:56 pm
content: Wicked reverse engineering! And yet another set of video's to watch

author: TUAREG
author_rank: Newbie
timestamp: March 29, 2015, 05:55:40 pm
content: Hello, my name is aitor, and i live in the canary islands, i saw this post, and i think it will be interesting to show another part of the apollo saturn 5 guidance and control computer that i have in my collection.

author: SeanB
author_rank: Super Contributor
timestamp: March 29, 2015, 06:06:48 pm
content: Time to get Mike to wind up the Xray scanners and send him something to image...........

author: Kjelt
author_rank: Super Contributor
timestamp: March 29, 2015, 08:11:20 pm
content: They look like relays.Wish I was at the canary islands right now, love the weather

author: SeanB
author_rank: Super Contributor
timestamp: March 29, 2015, 08:16:02 pm
content: No, potted modules, that epoxy was very common in the 1960's and 1970's as an encapsulant. Hard, low thermal expansion and resistant to a few of the more common solvents. Does survive moderate heat, and keeps what is inside safe and free from shock.

author: TUAREG
author_rank: Newbie
timestamp: March 29, 2015, 08:30:25 pm
content: could this board be the same as the one in the left pictured?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: March 30, 2015, 02:43:13 am
content: Hmm I used to have some IBM SLT modules but I can't find them right now. IBM really pioneered many concepts in packaging back in the 1960s and reading some of the old stuff, it could have been written last week. Face-down bonding of die, computerized testing of assembled modules, etcyoutube is filled with IBM videos of the era.

author: android
author_rank: Regular Contributor
timestamp: March 30, 2015, 12:17:11 pm
content: As someone who has worked withIBM (mainframe) equipmentfor 35 years I couldn't help but notice the familiar device numbering system on those chips. For as long as I've been in the industry IBM has numbered pretty much everything - hardware, software, manuals, you name it - with 7 digit codes. The code is usually made up of a 4-digit "device type" followed by a 3-digit "model number". Over time the digits became alphanumerics. In addition, any optional extras for a particular devtype/model are usually identified by a 4-digit "feature code".I have no idea whether that convention was in force when the chips were manufactured, but if so it's remarkable that it has lasted to this day.