Altair prototype

[falter]

Has there ever been any photos or such of the original Altair 8800 prototype (the one with the stacked boards) other than what was in Popular Electronics? Or schematics? I'm thinking that was the one that got lost in the mail famously, but I wonder if the foil patterns or any other, clearer photos of the boards ever surfaced anywhere.

This one is probably well outside the realm of possibility with so much info missing, but just to practice taking imperfect images and try to follow them, I messed around with the ones from the magazine. It's an interesting design.. seems to rely on zillions of little pads to attach ribbon cables to.

 

[hmb]

Has there ever been any photos or such of the original Altair 8800 prototype (the one with the stacked boards) other than what was in Popular Electronics? Or schematics? I'm thinking that was the one that got lost in the mail famously, but I wonder if the foil patterns or any other, clearer photos of the boards ever surfaced anywhere.

This one is probably well outside the realm of possibility with so much info missing, but just to practice taking imperfect images and try to follow them, I messed around with the ones from the magazine. It's an interesting design.. seems to rely on zillions of little pads to attach ribbon cables to.

My understanding is the prototype with 4 stacked boards interconnected with multiconductor cables as pictured in the Popular Electronics article was likely a "one-off" and the reason they had to resort to using a photo of the design prototype was, as you pointed out, because the first "production prototype" was lost in shipping. The designer's intent was for the final product to have a bus design with pluggable boards, as briefly described in that same article. If you requested the manual and board layouts from MITS as advertised in the article (as I did right after reading that article in December 1974) what you received were the S100 board schematics and foil patterns, not those of the design prototype. Without access to any other information about the Altair in those early days, I remember finding it odd the board schematics and foil patterns I received from MITS had no resemblance to what was pictured in that January 1975 Popular Electronics article.

 

[falter]

Thank you! Yeah that would make sense. I wonder what happened to the design prototype, or how closely it adhered to the basic circuit of the Altair. I'd love to make even just a visual replica of it, but the pictures are brutally poor quality.

 

[vwestlife]

Are you including the "prototype" that did nothing except light up the LEDs?

 

[falter]

Are you including the "prototype" that did nothing except light up the LEDs?

I'd love to build a replica of the fake cover unit.. not sure what it was constructed of though.

But really I'd like to replicate the first prototype 'stack' they made, even if just visually.

 

[falter]

So I asked Gemini AI if there was a way to take the photo of the original Altair prototype board and clear it up. I was expecting it to just tell me 'you need a better photo' or give me tips on how it might be done, but instead it just generated this.

Definitely some errors, but it's not way off. I'm impressed!

 

[Hugo Holden]

That is interesting. Can you post the image that you gave to the AI as well, so we can see what it managed to do.

 

[falter]

Here's the original. Bear in mind, I had to do some corrections with this as it was shot at an angle. I may not be accurate.



I'm trying to figure out what is a pad with a thru hole vs just a pad. It looks like the bottom area is just pads which I think they attached their ribbon cables to. It looks very hastily put together, even the cutting is kind of off kilter. It just looks kind of bizarre to me, like the 'comb' on that the lower of the two thick traces there. I'm thinking it doesn't conform to the final schematic at all.

 

[daver2]

A pad with a thru hole invariably has a track on the other side of the PCB.

Was that what you were asking?

Dave

 

[falter]

A pad with a thru hole invariably has a track on the other side of the PCB.

Was that what you were asking?

Dave

What I meant was, I can't tell which pads in the picture have thru holes and which ones don't. I think the mass of them at the bottom of this PCB don't possibly - I think they just soldered flat ribbon cable wires to them? Hard to tell. Wish there were better photos!

 

[daver2]

I would hazard a guess that this is a 'sea' of pads, and that the top pads that have PCB tracks attached to them may have vertical tracks linking the pads together vertically.

This would mean that you could solder multiple connections (up to 4) to the pads that are attached to IC pins on the board.

Now what they did with the other pads is another question (as to whether there are PCB tracks on the reverse side of the PCB)...

Dave