Apollo Guidance Computer Part 3: Main Bus B Undervolt

In preparation for the AGC power up, we test the alarm module B8, simulate the Apollo 13 main bus undervolt, and discover that our memory is faulty. And we find out how much our AGC did originally cost.

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[Ntech]

Awesome video! Shows how specific the application of the AGC was. Our smartphones may be faster etc etc, but this system performs a very specific job using logic and analog circuits. It's so awesome to watch y'all break everything done and explain what y'all are doing. Makes me appreciate what NASA managed to do 50 years ago even more.

[kallewirsch]

No way!
5.000 Volt after 50 years - spot on to 3 digits
That's impressive!

[michaelrouleau]

I think you men are restoring a national treasure.. Awesome videos.. Your work is very important for historic significance in electronics as well as national pride.. This stuff is inspiring..

[aubmckibben]

It's amazing that these modules survived the scrapping that took place. Great work by you guys. Just brilliant!

[contra]

I love this. I think that what you and your team(s) are doing is great. I think it goes along with what Eisenhower said. "Get it all on record now." Before the engineers and pioneers all pass away, get a history of how this was all implented and made to see how they did it back then so we never forget how revolutionizing they were in computers and electronics. Thank you for work good Sir.

[trainingtheworld]

Amazing to see you guys work on this. This thing was built to last!

[budude]

Easily my most anticipated channel to watch - - great stuff!

[daniel]

I love your videos! I can watch them again and again. It's amazing you are showing us huge piece of history <3

[flymario]

OMG! You guys are so very very cool! Its hard to actually believe you are working on this! My word.

[shoutitshauncy]

Looking forward to part 4 of this amazing project. Haven't got a clue what you guys are talking about, but I'm intrigued nonetheless! All I here when you guys talk is "flux-capacitors and 1.1 gigawatts"!!

[douro]

"Houston, we've had a problem...we've had a Main B bus undervolt."

1.8kbits of core rope memory from an HP 9100A- this is probably the most common example of its use:
(To understand how this can be 1.8kbits, there are 29 toroids and 64 wires. A wire passing through represents a 1, and the wires can be passed through multiple times. The HP 9100A had a 29-bit data word, and there are 64 wires for selecting the bits- this makes for 1, 856 bits of memory.)

[patrickturner]

For some reason this reminds me of when I was a kid of about 12 adding new parts into my IBM AT system. Big bulky cards and blocks. LMAO. The fact that we now have one chip that does the work of that entire case of transistors thousands of times faster is mindblowing. it's like looking at Steampunk tech. Steampunk Tech took us to the moon.

[MikeBramm]

I'm on the edge of my seat and you've left me hanging. Stay tuned...

[Dustycircuit]

You guys are awesome! Thank you for sharing!

[Membrane]

The alarm model is a very clever design.

[recklessroges]

Its like the special operations team from a Hollywood movie, but rather than actors you have the people that know what they are actually doing. Seal Team-6 of circuit computers. Digital historians. (I'm really impressed.)

[totolastico]

i wont be able to sleep until next video J'ai hâte.

[ElectricGears]

It might be worth looking into if it's possible to melt or dissolve the potting material so the memory can be repaired.

[yorgle]

You know, i was thinking about the inhibit line being broken; If my understanding of how that functions, and knowing that the core memory produces analog signals... should it be possible to still at least read it by monitoring the multiple voltage/current levels that are produced by reading it? or is it due to the procedure of charging it to read it going to completely mess it up? (I've only got a basic understanding of core memory...)

[SidneyCritic]

I guess B8 is like an early self test you find in latter oscilloscopes.
Considering this is so complex, and that Russian electronics on EEVblog is so far behind, I wonder what Korolev put in his rockets that got people like Gagarin into space.