The Apollo Saturn V LVDC Project - Page 1
Forum section: electronics / general

author: Frantone
author_rank: Regular Contributor
timestamp: July 15, 2013, 11:36:07 pm
content: From the video:A viewer donated an LVDC page assembly board to me that had been exposed to the elements in a salvage yard for over 40 years - so that it could be disassembled and destructively reverse engineered down to the component level, so that once and for all the real technology beneath the surface could be understood, that could explain how the Apollo Launch Vehicle Digital Computer really worked.And you can get a chance to be a part of it too!This genuine LVDC board does not belong to me, or to any one person - It belongs to all of us. When I complete my initial investigation, I will be passing along this Apollo Saturn V LVDC board to another engineer... Who in turn must pass it on to another engineer.... and so forth... in order that this artifact will forever remain in our community, and that we may all have a chance to share and discover this piece of history for ourselves.It is The Apollo Saturn V LVDC Project, starting soon!

author: Vgkid
author_rank: Super Contributor
timestamp: July 16, 2013, 12:06:43 am
content: This is very cool, I'am looking forward to the updates.

author: nctnico
author_rank: Super Contributor
timestamp: July 16, 2013, 12:19:33 am
content: Doesn't it need software to do something meaningfull? How about other boards and I/O?

author: poorchava
author_rank: Super Contributor
timestamp: July 16, 2013, 09:22:40 am
content: Well, I suppose this board is a single logic module, realizing some basic logic function like adder, multiplier, shift register or something like that. So once the schematic is figured out it will probably be rather easy to get it to run.

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 16, 2013, 06:14:59 pm
content: I'm still wondering how you know that this board (and the other one you have) are from the LVDC. I can't find the numbers of the boards in the LVDC maintenance manual, the only boards starting with 6112 are terminal blocks, see attachment. Do you have any 'secret' documentation?

author: seth13699
author_rank: Contributor
timestamp: July 16, 2013, 06:53:08 pm
content: There seem to be a lot of discrepancies between that lab manual illustration and what the "flight ready" units where equipped with. For example I can't find my page assembly anywhere in the documentation (unless I'm blind):which is clearly part of a "flight ready" spare LVDC (hence the no "non-flight ready red mark" on the top) :but clearly a part of the system nonetheless...

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 16, 2013, 07:07:48 pm
content: Hmm well, it looks like the real number we are looking for is not the one on the pcb but the one on the plastic support.I also have a manual with the diagrams of all the assemblies, so just count the ports on the pcb and it should be easy to find which one it is

author: seth13699
author_rank: Contributor
timestamp: July 16, 2013, 07:14:25 pm
content: The page assembly structure support frame is metallic btw. I'm pretty sure it's some kind of magnesium alloy.

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 16, 2013, 07:25:26 pm
content: Quote from: seth13699 on July 16, 2013, 07:14:25 pmIt is, I read it somewhere in the 100MB documentation, but I'm not going to find it againBut for anyone willing to try, here are the goodies:http://www.ibiblio.org/apollo/links.html#LVDC

author: ddavidebor
author_rank: Super Contributor
timestamp: July 16, 2013, 08:32:10 pm
content: Quote from: PA0PBZ on July 16, 2013, 06:14:59 pmWhat, where, who??? The are public documentation about inside the apollo? I can't find in on google, where can i find it?

author: Unknown
author_rank: Unknown
timestamp: July 17, 2013, 08:46:30 am
content: Quote from: ddavidebor on July 16, 2013, 08:32:10 pmTry the Saturn V LVDC lab. manual - makes for a very interesting read!http://klabs.org/DEI/Processor/apollo/19730063841_1973063841.pdf(edit)..This page has a lot of really nice docs.http://www.ibiblio.org/apollo/links.html

author: Frantone
author_rank: Regular Contributor
timestamp: July 17, 2013, 02:23:09 pm
content: No component level schematics of the LVDC exist in the public realm, which is the reason for the Apollo Saturn V LVDC Project. The goal is to assess the basis and function of the numerous logic devices that were used in order to better understand how the LVDC operated. If the logic devices themselves are understood, then the logic page assemblies that are in private collections can be mapped out and a schematic can be created. Systems level functions are documented, but exactly how accurate or correct any of that documentation could be to the flown LVDC's is unknown. Because of the complete absence of component level specific documents in the public realm I suspect that the public documentation is not accurate. It would be great to ultimately be able to download the core memory, which still exists in private collections, and one day build an operational reproduction of the LVDC system.

author: @rt
author_rank: Super Contributor
timestamp: September 22, 2016, 02:45:04 am
content: HiI don't suppose anyone is going to look at the YouTube vid comments, so if the board is still on offer for a project, I'd love to incorporate one of the transistors into my project that already uses my 64 bit core memory, which I think is still the largest modern core module. I have tested it to retain it's data without power for a 3 month period. The data was my location stored as a pair of 32 bit floats, and the TI H bridge chips are power cycle glitch free, so I do think that the older memories could potentially be read (with great difficulty figuring out addressing organisation).

author: Steven Pietrobon
author_rank: Newbie
timestamp: July 09, 2018, 06:31:51 am
content: The circuits for the INV, AA and AB modules (Frantone's board uses the INV and AA modules) can be found inNAS 8-11412https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660026443.pdfUnfortunately, I have no idea what the 321, 322, 323 and 324 modules on the junkpile board are. They aren't listed in the Simplex Model manual, although the board shown in Figure 1-3, has some of those modules.seth13699's board looks to consists of some of the other modules. I spottedDD Disagreement DetectorTMV Used in Module SwitchingVI Inverter (can drive up to 10 AND inputs)HCI High Current InverterCLN Resistor NetworkDDI Disagreement Detector InverterFP Flat Pack (two transitors in the green package)Looks like you have one of the voter boards. As the Simplex Model used only one channel, it used special voter modules with many modules missing (NU in the schematics). Yours looks like a full module and thus won't be listed in the Simplex Model manual.Yes!!! I have found seth13699's module! It is a Memory Timing Voter. The schematics are in Figure 10-30 (Sheets 1 and 2), pages 10-112 and 10-113 of Volume II (pages 156 and 157 in the pdf).Unfortunately, I could not find a match for Frantone's board. This could be due to different circuits being used in the flight model (we only have schematics for the Simplex Model) or the circuit is from one of the many other modules IBM made for the instrument unit, for example the Launch Vehicle Data Adaptor (LVDA).