posted 10-10-2019 02:35 PM               

For starters, though, am I correct in thinking that your AGC has part number 2003993-051?

posted 10-10-2019 03:19 PM               

If it still has the DIGFLY ropes in it, then I'd expect their part numbers would *probably* be something around 2010802-5xx or 2010802-6xx, depending on whether the DFBW ropes or the Skylab ropes were released first. We have so little information about DIGFLY that I'm not even entirely sure how many rope modules it took up! I do know that it contained all of the original AGC self-test code that was stripped out of the manned flight ropes to make space, so perhaps it was not all six.

Also, for what it's worth, LM-12 flew with a 2003993-091 AGC (likely, but not definitely, s/n RAY 56), so the change wasn't DFBW-specific.

posted 10-10-2019 04:14 PM               

It's P/N 203993-091, S/N Ray 26.

The memory modules are all 2003972
Memory B1 -011 Ray 86
Memory B2 -091 Ray 87
Memory B3 -111 Ray 115
And the memory jumper modules are 2003076 with -021 and -031, and S/N Ray 1, 2 and 5.

posted 10-10-2019 04:45 PM               

quote:

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Originally posted by Jurvetson:
this this AGC++ you connected me to

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posted 10-10-2019 05:10 PM               

• "DFCS Interconnect Harness A" with "STAGE III SIM & FLT" and S/N 2 Part No. "MX117926 NASA/FRC DFCS"

• "Interface Box Assembly" each with "STAGE III SIM & FLT" S/N 1 Part No. "MX117925 NASA/FRC DFCS"

• Apollo G&N System Power & Servo Assembly - LM P/N 6007200 S/N AC 14 Cont. No. NAS 9-497

• IMU sphere with P/N 2018808 Rev E, Cured 1-67 Mutron Corp.

posted 10-10-2019 10:58 PM               

There's a lot of really interesting things about this. I think the number you're seeing on the IMU is actually 2018806; that is the part number for the insulation for the left hand case heat exchanger.

2018808 is a weight used to balance the stable member.

The IMU itself should be 2018601.

The Coupling Data Unit is on the shelf directly above the AGC. Its part tag will be on the front left corner of the top cover, when facing the big harness that plugs into it. It looks pretty well obscured by the shelf above it, unfortunately.

It's really interesting that they've removed the DFBW ropes and gone back to Aurora — I wonder what it was that they were testing that DIGFLY couldn't do. This G&N System Inventory from 1969 indicates that these modules constituted "Set 8" of Aurora, and were assigned to (and very likely installed in) LM-8. The AGC installed in LM-8 at that time was s/n 49, though.

As for your AGC — as far as I can tell it didn't have any formal assignments before DFBW. Its designation was computer C-12. Here's what I've been able to find of its history:

It was most likely born at the very end of 1966, or in early 1967.

On July 25, 1967, a technical report was written describing a restart that happened on C-12. (The title of this report is listed on this PDF page 84, but we don't have the report itself). Apparently, at this time, it was stationed at Grumman for potential use in a LM. It may have been installed in a LM at some point, but right now I think we only know dash numbers, not serial numbers, for that time period.

According to page 244 of the same document, in early-mid 1968 it was affected by ECP 696, "Recycle of AGC's for Incorporation of Changes." Presumably, up until this point, it had stayed at Grumman, and had not been kept up to date with hardware modifications that had been made. It was shipped to AC or Raytheon for updates.

In June 1968, presumably while being re-tested after the ECP 696 changes, two of its NOR gates failed due to loose conductive particles during vibration testing. Four months later, in October, a third failed in another vibration test. These are listed on this PDF page 41.

After that it seems like it was kept at AC Electronics as a flightworthy computer. This memo from August 31, 1970 lists it as a spare at AC.

This memo from October 6, 1970, which discusses hardware available for use for Skylab, also mentions it as a flightworthy spare located at AC.

I can't speak much to the other parts, unfortunately. All of the MX* stuff is non-Apollo, and the National Archives don't have the drawings (or at least, not in the same collection as all of the Apollo drawings). It looks like custom stuff built for the DFBW tests.

I'll keep an eye open and let you know if I find anything further!

On edit: Hahaha, nevermind, it was installed in a LM! As of December 1967, it was installed in LM-2 as part of guidance system 608, as shown on PDF page 31 of this System Status Report.

posted 10-11-2019 10:24 AM               

So, amazingly, my AGC started its life in the Lunar Module that is on display in the Smithsonian... wow.

posted 10-11-2019 12:05 PM               

The Aurora rope modules don't have any flight software (Apollo 14 or otherwise) in them, unfortunately. But what they do have is a large set of very extensive system tests for all of the LM hardware. There's a large chunk of code dedicated to self-testing the computer -- it checks every control pulse of every instruction, writes to and reads from every memory location, etc. There are a bunch of inertial test routines which torque the IMU around, where the operator verifies the correct alignment was achieved based on FDAI displays. There's routines that will fire each of the RCS thrusters in a sequence to make sure they all work and the mapping is correct, routines that take the descent engine through various throttle settings, etc.

All of this test code was extremely useful for checking out LMs, but also took up a lot of space in the limited memory of the AGC. Some of the computer self-test routines (the extensive divide/multiply tests) were deleted from the Apollo 5 flight ropes to make room, and by the time of Apollo 9 pretty much all of the test code had been deleted to fit all of the flight code in.

posted 10-17-2019 11:37 AM               

I see you got a DSE on display. Just to clarify, it does not have any tape right?

If it does, even a little bit, that may be interesting to get digitized. As long as it has the heads this should be possible...