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Compucorp 625 II

C

cesare

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Joined
Mar 23, 2024
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I'm wondering if anyone has any information about these machines - my attempts to find anyone else with a working one has drawn a blank so far.

The machine is an S-100 design, with dual 5.25 floppy, a printer and video controller along with a processor board. My example had a dodgy video RAM chip, and some dodgy capacitors in the VDU, but sorting these out gets me to the point when the machine is now attempting to boot from floppy, and the display characters are correct, and pretty stable:

jaDJXvu.jpeg


I happen to have a disk which thinks it's got the OS on it (zebra) although it is failing to boot, but given the age of the disks and the age of the drives, and the not-so-fantastic decision to mount these vertically, it's not clear whether I should tear down and clean a drive with the hope that it gets things further along.

Anyhow, an enjoyable project so far, and if anyone has any info about these, it would be greatly appreciated.

Some snaps of the inside for those interested:

GInWtFa.jpg


ZNWRalu.jpg


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oY1aHKD.jpg
 
Yeah, the vertical floppies are weird, it could have had a tandy TRS-80 layout if it wasn't for the printer. It suggests the printer was more important. Given the company made plenty of calculators, i'm guessing this is aimed at accounts/payroll type applications, and the integrated printer is probably taken from that world and was probably what people spent their day doing rather than swapping floppies. Of course it might just have been a terrible design, and the fact i've not seen another one ever does rather suggest something wasn't quite right with it.
 
That is one seriously strange computer. The fact they put the printer up front and not the disk drives?? Also seems strange to mount the CRT on the right and not on the left (more in line with the alpha keys).. it's baffling and I love it! Hope you can find some more info on it. You should probably do a dump of those EPROMS.
 
Whats going on with the floppy drive doors? Those blue things; seems like the flappers are missing and those were put in their place.
 
They are micropolis 1015 drives, and the blue part is blue anodised I presume aluminium. They seem to operate as expected, pulling down to lock the mechanism, in place, although the disks do not eject very well, old gummed up grease I presume, the springs look to be intact. Given i've never seen even a picture of one of these anywhere else, I really can't say whether this is original to the machine!

I think giving a drive a tear down and clean will be worth doing, if only to make the mechanism operate more smoothly.
 
The 1015 shipped in two varieties: Mod I drives have a track density of 48 TPI/35 tracks and Mod II drives have more capacity with 100TPI/77 tracks.

Generally, the blue eject lever was used on Mod II drives to differentiate them from the (incompatible) Mod I drives, since otherwise they can look identical. Probably a bit of marketing spin as well.

I've never seen them mounted vertically! Mounted horizontally the eject mechanism is fairly modest... on my drives the floppy ejects about an inch, just enough to grab it, so I can understand why yours may be struggling. Out of curiosity I checked the service manual and it says:

"2.6.2 Specific Mounting Requirements

The drive may be mounted in any orientation except upside down. If the drive is to be mounted with the bezel UP, it should be ordered as such so the disk eject system can be suitably adjusted."

So you may see some improvement if you adjust the springs a bit, if cleaning/lubing doesn't help.
 

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The eject is not strong - i've given them a clean, but i've a feeling that's not the issue. The disks actually interfere with the plastic clamp in the mechanism when inserting or removing the disks, so there is plenty of resistance from that when trying to eject disks, and this seems to be the main issue.

Here's a more recent photo. This is as far as I can really get with the machine without software.

nMvtJNx.jpeg


I have cleaned the case and removed rust, and primed the previously rusty parts. The black around the keyboard got stripped and repainted, not very well, but good enough that it is not getting any worse. There is plenty of discolouration on the texture on the outside of the case, and missing texture on one side where I presume it's been in the sun and it's deteriorated.

The only other thing I might do is try and extract the ROMs, as these don't appear to be preserved anywhere, and might give some insight into what the expectation for the drives and boot process is. The drives spin their disks and attempt to read I presume boot code from both, with the occasional seek suggesting they occasionally get something off the disks I have. I've also yet to find any other working example, which is kind of surprising, this can't be the last of these out there can it?
 
Hello,

Anders from Sweden here... I recently rescued a ton of old computers from an estate and one of them was an OG CompuCorp 625 (not the II) that I will be looking at restoring. There may also be some diskettes for it.
So any information or documentation you may have is of interest as I am starting up a retro computer museum and would love to have as much stuff as possible in the exhibit in running order.

2024-09-08 19.07.56.jpg

Regards,
Anders
 
Hi Anders.

It's good to see you've got another survivor from this era. It's looks to be in roughly the same condition as my one, with everything intact but somewhat dirty and rusty. My fibreglass case has missing texture on one side, probably sat in the sun, but giving it and the plastic inserts for the printer and drives a clean with ambiclens and it came up great.

Internally, I disconnected the printer, and removed the drives to reveal the PSU boards underneath. Powering it up there was nothing obviously wrong, and the power rails looked stable, so I have no experience with that side of the machine.

I had problems with the VDU being unstable, and replaced capacitors on the display cards to resolve this. I've attached the service manual which covers this display.

The processor card and main memory appeared to work, and I only had issues with some failed 1k ram chips on the display card, initially giving me scrambled display characters. They were socketed so it was pretty easy to source and install replacements for these. I removed and measured some of the capacitors around the cards, and they measured fine, so i've left these alone.

So at this point, i've got reconnected the printer, i have no way of testing this, so there felt like little point till I get the machine to boot to something that can talk to the printer.

The drives on your machine don't have the blue anodised levers from the look of it, so may be the lower track count disks mentioned by Selectric earlier in the post, so these are i'm guessing going to be incompatible with the drives on my machine. It might be the driver card is able to support both though.

I'll be very interested to see how you progress and how things turn out for your machine. I've got distracted with work, and getting some old Macs up and running recently, but this machine is still waiting for me to see if I can get it further along.

Cesare
 

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Hi Cesare,
Thanks for the prompt reply! Yes it makes sense for the drives in this one to be 160k drives. I am just finishing off getting two of my other CompuCorp machines (mod 655) up and running and the older one of those also have 160k drives.
All of the old CompuCorp computers seem to be running the Zebra monitor/OS and I am searching for any kind of manual or documentation for this OS in order for me to be able to make copies of the boot diskettes I have.
What I do know is that it is hardsectored disks with 16 sectors and I would expect these to be similar.
/Anders
 
Hey Starcat,
Thanks for letting me know... I have gone to register on their forum and hopefully something can be worked out.
As I mentioned I now also have two working CompuCorp series 600 model 655 computers and they also run a version of the Zebra OS.
So with the manual I should be able to make duplicates of the bootdiskettes I have for these systems on physical media.
I will also try to make a setup where I can make flux-images of the diskettes too.

2024-09-08 15.56.18.jpg
 
i used to work servicing the compucorp computers mid 80's
i have lots off software that i started to archive.
i will upload some diskettes here gridcontroller.net
 
hansit said:
i used to work servicing the compucorp computers mid 80's
i have lots off software that i started to archive.
i will upload some diskettes here gridcontroller.net
Click to expand...

I'd definitely be interested in any 625 disks, and i'll look into ways of making copies of the disks I have, on the off chance that the disks are good, and it's the drives that need a service...
 
can you check what make and model the floppy drive has in the 625.
so that i archive the floppys with the correct format.
 
hansit said:
can you check what make and model the floppy drive has in the 625.
so that i archive the floppys with the correct format.
Click to expand...
I will verify the drives in all three different CompuCorp machines that I have but only the Series 600 Model 600 and Series 600 Model 655 are up and running for now though. I think that the Series 600 Model 600 and the 625 have the same drives but I will verify!

Also, do you have any tips on how to write the images onto either hardsectored media in the original drives or on non hardsectored drives? Or maybe create the media with either a Greaseweasle or Kryoflux?

I have a VSG (Virtual Sector Generator) from DeRamp that may be of use but I haven't tested it yet. Also I thought of potentially using a Gotek as one of the drives in the original machine and then copying the disk image over to physical media that way...
 
hansit said:
can you check what make and model the floppy drive has in the 625.
so that i archive the floppys with the correct format.
Click to expand...

The drives are Micropolis 1015 mod II
 

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Not sure I can be much practical help but, the Compucorp 625 mark II was the very first computer I ever owned (albeit briefly).

When I was 14 or 15 years old, my grandfather wanted to encourage my interest in computers and somehow acquired 2 of these. I suspect they really weren't all that old at the time. Now in my late 50's, I still have fond memories of those days and have been looking for one to restore here in Australia for many years now.

Perhaps sadly, for some reason the two I had, had to be returned to the seller (a friend of my grandfathers) who had sold them without permission or some such thing, so I only had them for about 8 months I think. Still with the money that was refunded I bought an Apple II and moved on. Still I have to attribute much of my love of computers and tech to this early machine.

If anyone has one of these in Australia that they'd like to see have a good home, or hears about one being available I'd love to hear from you.

Good luck to the OP in restoring this amazing bit of history, and congrats on a great find!
 
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