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Finally got my MCM/70

Well if you ever decide to teach a course on acquisition outside of ebay please let me know. :) I hate being reliant on that place for the majority of my 'finds'.

Really hope you do get it powered up. Would love to see what it does.

I'm curious if the serial tells us anything about how many were likely produced.
 
falter said:
Well if you ever decide to teach a course on acquisition outside of ebay please let me know. :) I hate being reliant on that place for the majority of my 'finds'.
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I would say my best finds are NOT on eBay but it is a major source. There are a few things one can do but if I gave that away, i would never find anything anymore ;)

falter said:
Really hope you do get it powered up. Would love to see what it does.
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Me too! I did learn from the original owner that when he said it wasn't working, he meant that if powered up the last tie be tried 10-15 years ago but it showed random moving dots. That sounds promising but it's like a Chinese puzzle box to take apart. Not being around this weekend, I can do anything so it waits for now.

falter said:
I'm curious if the serial tells us anything about how many were likely produced.
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No, I don't think so. Serial number is D509118. Could there have been 9118 produced? I don't know but I think that number is lower.

MCM70 Before - rear label.jpg
 
nigwil said:
Did the emulator ever get released somewhere?

If the MCM/70 EPROMs could be captured then it would be great to see it running on a 8008 emulator.
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There is an emulator for the MCM/800 but I don't think that has been released. It is different from the MCM/70 as it does not have an Intel 8008 but has something similar built from discrete logic. I will see if I can read the ROMs if I ever get to taking it apart. The boards are not easy to access at this point. I'l have to try again next week.
 
I was able to take a quick pic of the card cage/power supply of the MCM/70. The card cage is located in the back thick part of the wedge. The black back metal panel is a large heat sync. There is no fan in the computer. I think this is the whole power supply shown. Below that board is a series of other boards that would make up the rest of the board set. I still have to figure out how to take those boards out. I was expecting a few large filter caps but there are none. 120v is plugged into the bottom right directly. The boards are wired for power individually from the top left red/green wires. There is no back plane from what I can see.

MCM70 - Power supply and card cage.jpg

Bigger picture here.
 
Love those stud-mount diodes! If you're interested in prophylactic measures before powering things, check the electrolytic capacitors; remove the socketed ICs and give them and the sockets a spritz of contact cleaner. You could also test the diodes. Otherwise, the power supply looks pretty simple.
 
I put some some more internal card pics as I take it apar and photograph the MCM/70. Being commercial, there is very little I can remove without desoldering. I can't read the ROMs as they are not removeable 1702A EPROMs. I am already seeing local help from Josh.

These are pics that will go away once I complete a decent page or two on the MCM/70 but it's where I am putting pics as I take them.

http://vintagecomputer.ca/mcm-70-pic-dump/
 
thank you for the video.

Wonderful to finally see a live MCM/70 after all these years wondering what they looked like working.

I hope the EPROMs can be read so we can keep it alive forever on an 8008 emulator.
 
nigwil said:
thank you for the video.

Wonderful to finally see a live MCM/70 after all these years wondering what they looked like working.

I hope the EPROMs can be read so we can keep it alive forever on an 8008 emulator.
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So do I. I'd like to add it to my emulators. This one( https://hackaday.io/project/161404-videops2-keyboard-8008-system-emulator) does 24x80 NTSC video and PS/2 in addition to the 8008 emulation, all from a $3.00 ESP8266 and junkbox parts.

I wonder if the display is made of dumb MAN-2's or some smart display or subsytem. That, and scanning the keyboard, might make emulation trickier. The tapes, I could probably do in flash. Hopefully some schematics exist somewhere.

That MCM-70 was really ahead of its time. I wonder what the designers went off to do...
 
I would like to second making the ROMS available if possible (although we may not be able to do much with them unless we can get hold of a schematic due to the memory 'tricks' that were pulled.

I did try to get hold of a copy of the ROMS and the manuals - or the emulator - but to no avail.

I did a "Hello world" (or more correctly "Hello Dave") APL example for the Commodore SuperPET that I can dig out for you if you like...

The download website is here http://mikenaberezny.com/hardware/superpet/waterloo-languages/ but I can hunt out the specific file if that would help?

Good going to getting the unit working though!

Dave
 
Thanks guys. I had already offered up my computer to have the ROMs dumped by someone who knows how to do them without removing them and there are two versions that have already been dumped so it is not needed.

There is also an emulator that is almost done for the MCM/70 that has not yet been released. To help out, I have been asked to type in a game written in APL and take a video of the output so that the emulator output can be confirmed to match the real MCM/70 or adjusted. There is some glitching of the screen that is normal because the firmware uses display memory for temporary variables; allowing more RAM to be used for the APL system. I wonder if that will be emulated? The display is a 32 character Burroughs Panaplex self-scan display.

There are no existing schematics for the MCM/70 that are known to exist. The manuals I have and have scanned them to this directory but there is not much technical information there.
 
I wonder, as a theoretical exercise, if you could build a replica/clone of an MCM-70, assuming you had the schematics. I've had some success taking photos like the ones snuci was kind enough to post and then using Photoshop and schematics, converting them into PCB artwork. I realize this is a fairly complex machine of course.

You can still find the burroughs display, you can make the PCBs and probably find all of the support ICs. The tape decks would be probably too difficult (but you could probably find a workaround). The ROMs would be the one thing I imagine would be really hard if not impossible to recreate in their original form?
 
I was hoping to have a go and put the ROMs into my JavaScript 8008 emulator (with the expected tweaks).

Snuci, you say there are two versions of the ROMs that have already been dumped. Are they online anywhere by any chance and, if so, are you able to point me at them?

Cheers,

Dave
 
daver2 said:
Snuci, you say there are two versions of the ROMs that have already been dumped. Are they online anywhere by any chance and, if so, are you able to point me at them?
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I don't believe they are public. I will ask the person who has them if he will give me a copy and see if he has any issues sharing them. I, personally, would share them if I had them as more emulators could only strengthen the knowledge of these computers out there.
 
Thanks,

I am disassembling your boards at the moment from your photographs...

It's starting to get late in the UK though so I may have to give it up shortly.

Dave
 
Nice :).

I have uploaded my first attempt at disassembling the RAM card to https://drive.google.com/open?id=1ajHsD5Jpz_6Ih92aSb7xKXcUheC-wjgy.

I am going away on a business trip this week - so I will take the photographs of the remaining cards with me and see how far I get...

I will use the J1 pinout from the RAM card to help with the ROM card. I suspect that the CPU/RAM and ROM cards all communicate via a shared bus - so the function of each pin on these connectors should be the same.

There are a few things I can't determine from the photographs - so I have documented these on the schematic(s) and will revisit them in dour course once I have disassembled the CPU card (if I can that is).

Dave
 
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