Teardown - Part of the Nebuchadnezzar (The Matrix)

[TerraHertz]

Well sort of. A teardown of something that was on the set during shooting, and was probably intended to be part of the Nebuchadnezzar, but didn't make it to the actual movie screen. Just some bit of random junk the set designers painted up in that grungy style.

However it's a bit of a mystery, what it actually once was. Anyone have any idea, or know any of its history?

http://everist.org/NobLog/20140910_Nebuchadnezzar_teardown.htm

[mikeselectricstuff]

That core memory is probably a keyboard->ASCII encoder - not really memory, but coupling selected inputs to outputs

[TerraHertz]

That core memory is probably a keyboard->ASCII encoder - not really memory, but coupling selected inputs to outputs

Actually I realized it wasn't 'memory' as such about 2 minutes after uploading the original, and changed it. Maybe you got a cached version?
Yes, it's just coding the keys to 8-bit binary values. But ASCII? I doubt it. Why would it? There's no processor.

I'm guessing it has a big (for those days) ring buffer of data values, and spins them round to make a 'digital sound'. With key presses just overwriting values in the buffer.

I've played with similar sounds, using a HP 8018A Serial data generator. Just run the output to my audio amp, and mess with the data in the memory via the panel switches. It makes some very trance-like complex sounds. But setting binary values for address and data via a row of thumwheels and toggle switches then pressing 'write' is a pain. The way this thing probably worked seems much better.
Still a near-useless sort of 'musical sound' generator though. It would grow stale very soon.

[mikeselectricstuff]

Maybe not ascii - division rations for notes perhaps?
What's on that other PCB (display?) and the one that the thumbwheels are connected to?

[Alex Eisenhut]

My first gut instinct was "tv typewriter" but that didn't have a speaker and had more chips... Oh well.

[TerraHertz]

Maybe not ascii - division rations for notes perhaps?

No, you're way over-thinking it. There's not enough logic for anything like that. Most of the ICs are 7400, 7404, 74121, 7410, things like that. Two Fairchild 3341, which are a 64 x 4 bit FIFO. Ha ha...  what I guessed they'd be. A 74157 next to each one, in line with those ferrite cores. I bet they are multiplexing in the new data into the current position in the FIFOs, when a key is pressed.

What's on that other PCB (display?) and the one that the thumbwheels are connected to?

The thumbwheels are just a two digit adjustable resistor. Only two wires to that block. Likely used to set the main FIFO clock frequency, via a simple oscillator.
The display PCB has two 74192 counters, two 7447 binary to 7-seg decoders, a 7400 and a 74121.

God I hated circuits that used monostables everywhere.

Hey, the LED just below the digital display is an orange LED. The power LED is green. Quite newly available back then.

[mikerj]

Have you tried powering it up?

[SeanB]

That is a rope core memory, not core but a ROM similar to those used on the Apollo flight computers.

I would guess it makes variable clicks or sound tones according to the key pressed, and possibly the BCD encoders select either a tone or a spacing between the sounds.  Kind of like those old movie effects where mainframe computers make beeping and booping sounds when in operation.

[TerraHertz]

Have you tried powering it up?

I'm trying hard to resist the temptation. Since the chances of it being a total, futile waste of time are about 99%.
But maybe...

That is a rope core memory, not core but a ROM similar to those used on the Apollo flight computers.

Goddamit, that 2 minute exposure of the 1st version, before I said much the same thing, must still be floating around in caches.

I would guess it makes variable clicks or sound tones according to the key pressed, and possibly the BCD encoders select either a tone or a spacing between the sounds.  Kind of like those old movie effects where mainframe computers make beeping and booping sounds when in operation.

Now you're trying to use reverse psychology to make me power it up (and get it working, without schematics.) Maybe...

I suspect it will sound more like digital data-stream bagpipes. Didn't you ever feed a cycling stream of bits into a stereo amp?
The two 64 x 4 bit FIFO's outputs go to a couple of 7495 shift registers, so it's probably generating a 512-bit sequence. Looping, since FIFOs. Enough for some interesting harmonics.

[SeanB]

If you do not want it find a box and I will send you a postal address to post it to then............

[Vgkid]

That is a rather unique teardown, thanks.

[T3sl4co1l]

I put my money on teletype or code modulated something or other.

Be curious to see what some of the codes are; if "A" (or what should be in the 'A' position for a QWERTY or alphabetical keyboard) comes to 01000001 and so on (or 01100001), it's probably ASCII or something closely related to it.  If not, maybe it is a sequential music box thinger or something

Tim

[mikerj]

I put my money on teletype or code modulated something or other.

That's what I suspect; it encodes characters and transmits them using simple on-off keying of an audio tone.  The thumbwheels are probably to set the transmit rate (e.g. characters/second (minute?), recirc to continuously send a message maybe?  The 60CH (60 characters?) lamp tells you when the buffer is almost full at a guess.

Can you read the label above the 1/4" jack sockets on the rear panel?

[n45048]

Some kind of early TTY or RF text sender input device?

[TerraHertz]

If you do not want it find a box and I will send you a postal address to post it to then............

I do want to get rid of it. Was intending to scrap it, but if you do want it, then sure, if you pay the postage I'll send it to you. But I think you can't be serious?

My curiosity is piqued enough now that I will try powering it up first. I'm busy the next few days, but sometime next week I should have time. It has tantalums, and various other things that are likely to be dead/broken, hence my initial reluctance to even bother trying. But I'll give it a go.

[SeanB]

So how much will it cost to post to South Africa, either air or sea mail?

[TerraHertz]

Still can't believe you're serious. But anyway, I found a suitable box. After cutting down it will be 410 x 310 x 200 mm.
Packed weight about 4Kg.
http://auspost.com.au/apps/international-parcel.html?searchCriteria.countryCode=ZA
Air Mail $127.20
Sea Mail $64.10

I certainly wouldn't spend that much on this piece of junk.
Anyway, next week I'll see if it works. But even if it 'works' it isn't going to do anything useful.

[n45048]

You could always ship it to Dave, he might be able to do a mini teardown on it for all to enjoy.

[SeanB]

I will pay the Post To Dave price. Nicer video and we all get to enjoy it.