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The Computerland desktop project

J

JonnyGators

Experienced Member
Joined
Mar 9, 2020
Messages
166
Location
Attleboro, MA
I mentioned this find on another thread, and it was requested I post about it. So here's the official thread on my newest project computer.

I believe it's a Computerland BC-88. The BC-88 and BC-286 came in the same case, with both part numbers on the case, so I took a chance bidding on it. But from looking at it, it has a video card and a card with parallel and serial port....I believe one of the differences is that the 286 has a 3rd card in it.

Hooked it up, flipped the big red switch, and.....nothing happened. Tried again, I can see the fan rock a little each time I do it.

Ok, time to open it up. Took out the screws....case won't come of.

Oh crap.....I think it's locked.

No keys included.

I'm not sure if the lock on this model prevents it from being turned on or not. But, I'm going to need to get the lock unlocked if I'm going to get in there. Uh.....how do I go about that? I really don't want to cause any cosmetic damage to the case.
 
Nevermind.....of course after I post, I do a little wiggling, and whatever had a hold on it freed up, and off the case came. Not locked.

And it has an 8088 processor in it, so it is indeed a BC-88.

Now to do some cleaning, and testing.
 
Ok, with the fan on the power supply not spinning up, my first thought is a replacement power supply is a good start. However....this power supply has a big red switch attached to it, which the case makes a cut out for. So, while I have found replacement power supplies that use a P8 and P9 connection, having a big red switch mounted on the side doesn't seem to be a standard.

Anyone know of a replacement option for a P8 P9 power supply with big red switch on the side? Yes....it's rather important to me to keep the original look and feel of that big red switch.
 
IBM and many clones had power supplies with a big red switch, but I have no idea if they are the same dimensions as what you have.

I’d probably do more troubleshooting before just replacing it. Maybe something is shorted causing it to shut down? And some power supplies won’t run unless they have enough load. So I guess you can have too much or too little in some cases. :)

I’ve seen some good videos recently about troubleshooting power supplies. One that I recall was a guy working on an Olivetti. Might be something to search YouTube for to get some ideas.
 
Good points, will look into that.

I did find an option on amazon that has those connectors for under $40 that can arrive by Friday. I'm not sure if I can rig it up to fit nicely in the case, but it's worth having something on hand for testing and troubleshooting at least. I'll check out some vids this week, and will have to do some tinkering this weekend.
 
Do you have a multimeter? You should check the motherboard for a short between the voltage pins and ground pins, which would indicate a shorted or capacitor on the board. The power supplies in these computers typically will not turn on (safety circuit) if there is a short on the board, and some people will mistake this for a bad power supply. Rule out a short capacitor on the motherboard first before replacing the power supply.
 
Also remember that most computer power supplies require a minimum load to run. So if you unplug it from everything and try to turn it on with nothing connected, it'll probably either run for a few seconds and then shut down or not run at all. Try testing the power supply with an old hard drive (preferably 5.25") as a load.
 
chris_nh said:
Do you have a multimeter? You should check the motherboard for a short between the voltage pins and ground pins, which would indicate a shorted or capacitor on the board. The power supplies in these computers typically will not turn on (safety circuit) if there is a short on the board, and some people will mistake this for a bad power supply. Rule out a short capacitor on the motherboard first before replacing the power supply.
Click to expand...

Well, the motherboard is pretty much just a board with slots. The processor is on one of the cards. Which, it turns out there are 4 cards in there.

1 - A card that includes the 8088 processor chip on it
2 - A card that the floppy drive connects to, has a parallel and serial port on it
3 - Video card
4 - A card that the hard drive connects to

So I decided to try the test to see if there is a short between the voltage and ground pins, adding the cards one at a time. First, added the card with the processor, no problem. Then I added the card for the floppy with the parallel and serial ports.....shorts out.

Tracing and finding problem capacitors, soldering out tiny capacitors, and fixing things on this level is just not a skill I have, or will ever acquire. Not even sure where to begin, and can't get much in the way of realistic help there....so I'm kinda stuck looking around for a replacement now.
 
Well, after some more playing around, I'm not sure there's a problem yet.

I cleaned up things a bit, and figured I'd try turning on the power supply adding things one at a time. It turns on with a drive connected, so that's a good start. Then I started adding the cards one at a time, and it kept humming to life every time I turned it on. Even got the familiar beep it gives after it finishes counting up the amount of RAM. I stopped short of connecting all the drive cables and the wires from the small front board that held the dead battery, and I don't have the monitor connected yet....gonna do some more cleaning and then start wiring things, but maybe all it needed was a little cleaning and reseating of the cards.

The front mini board is going to be the biggest pain in the ass, though. It's held together with 2 screws, one of which is determined to stay right where it's been for 35 years, the head is very stripped and I can't get a good grab with a wrench, so any work on it will need to be done without taking it apart. I tried to carefully pry the terminals of the battery, but of course the negative terminal broke right off the board. It's 3.5v, so if I can manage to get a wire onto the contact that the terminal broke off of, and get a 2032 holder connected and adhered to the spot somehow, I should be good there. That compartment has the battery, the lights on the front, and the lock mechanism.

Hopefully I can get everything cleaned up and put back together, and it will still fire up. I'll try to get some pictures posted tomorrow, and I'm hoping to do a video about this computer.
 
Hopefully I can get together and post some pics this evening.

A thought occurred to me though....I took a moment to do a quick search to find suitable DOS disk images for this computer online, since I'm not sure what's on the HD that's in there now, or if it even works. I know our family ComputerLand BC-88 came with 2 binder books, one for MS-DOS 2.11, the other for GW-Basic, although the each contained disks for both, so we had 2 copies of each. Which was good because one of the Basic disks was bad and would make the computer beep and throw random text when trying to run it. Anyways, I figure, ok, I'll go find an MS-DOS 2.11 disk image....but I see now that there wasn't a retail version, the only images I can find are OEM versions.

I can probably find something that works. Perhaps a version of 3 or 5 would be an easy option to get something working in a pinch. But, ideally I'd like to track down the version of DOS 2.11 that came with the computer. I've got a saved search on ebay for ComputerLand, hoping that an alert shows up in my inbox one morning with those books and disks. But in the meantime....if anyone happens to have that, or images of them, please do let me know.
 
As promised, here are some pictures

01 - desktop.jpg
The desktop, as it arrived

02 - inside.jpg
With the cover removed

03 - inside.jpg
A close shot of the cards, with the wires attached

04 - back.jpg
The layout of the cards from the back. The little red button is a reset button, on the card that contains the processor.

05 - inside clean.jpg
Another shot of the inside, with the cards put back in, a bit cleaner now.
 
It works!

Not sure why it wasn't turning on before, only thing that is different at the moment is there's no battery, and before it had a dead battery in place. Perhaps just taking things apart, cleaning things, and reseating all card was all it needed.

The hard drive powers up and sounds as you'd expect it to, but it won't boot to the hard drive. I grabbed what I happened to have on hand as far as boot disks go, which at the moment are Compaq DOS 2.12 and 3.10, from working on the portables. It doesn't like the 2.12 disk, but booted fine to the 3.10. Running the fdisk command, it sees the hard drive, but doesn't like whatever format or partition is on there currently. But, as I think about it, I don't think fdisk is a thing in DOS 2, which is what I expect the HD would have on it, so, perhaps the way it's setup is something fdisk won't recognize.

Anyways, I could try to wipe the disk and start anew, but.....I really don't want to do that without having a chance to see what's on it and try to retrieve the data on there. There's a chance it has a version of ComputerLand DOS 2 on there (I'm hoping 2.11), and I'm not sure when another readable disk of that is going to surface. Any suggestions what to do with the hard drive?


Next steps - cleaning the keyboard (it's filthy) and getting a battery holder solder in where the old battery was.
 
Since FDISK at least thinks there is a drive, then it would already be low-level formatted and matches the controller.

What I would do is try to get a copy of the norton utilities over there so you can view the physical sectors on the drive (DOS does not need to recognize the drive to do this).

Try scrolling forward through the sectors to see if there are any read errors. Looking at the sectors can give you some idea of what is on there. I'd avoid having Norton automatically fix anything until you have some idea of what the issue is.

What size is this drive? If it is 40mb or more, then it may be formatted to require DOS 4.0 or later.
 
I expect it to be a 20MB drive, but I'm not certain of that.

I found an IBM PC DOS 3.2 disk in my pile of disks as well. Weird thing, the fdisk on that doesn't recognize that there's an HD at all. But the Compaq 3.1 DOS still does. Even if I boot with the 3.2 disk, go into fdisk on there, see it say there's no disk, exit out, while still booted from the 3.2 disk I insert the 3.1 disk and run fdisk, it sees the drive. Not sure why one version of fdisk sees the drive and another doesn't see it at all, but that's what it does.

Thanks for the suggestion, I will work on tracking down a version of norton utilities that will work on it.
 
I tried out Norton Utilities 3.1 and 4.0, neither could see or access the hard drive.

Norton Utilities 3.1 acted different for different versions of DOS. It wouldn't run when I booted with Compaq DOS 3.1, but it did run on IBM DOS 3.2, and saw 5 drives, A-E. A and B being the single floppy drive, and it wouldn't let me select C, D, or E. I found a version of 2.11 that boots the computer, and running it under that DOS it only saw the A drive.

Norton Utilities 4.0 only saw the floppy drive no matter what I booted with.

I'm really striking out on finding a way to access the hard drive. There has to be a way. I mean, this did all work together at one point in time, and a version of fdisk does see the drive connected....if there's data on that disk, it should be retrievable. But how?
 
I've been investigating trying to find if there are methods or ways people are connecting drives of this age to modern computers with adapters to extract data, thinking that may be a route to go. Which led me to taking the drive out, and seeing it's a ST-225 hard drive, which led me to reading up on ST506/ST412. And I've not found much in the way of adapters to extract data. So....it seems I'm dealing with an old pre-ide format here. Which I know very little about.

I did manage to pick up a 2nd disk, which is on it's way here, so I'll have another one to play around with and experiment with. But I realize.....I don't know where to start with these. The earliest stuff I've dealt with involves using fdisk to partition. But I'm dealing with a computer that came with DOS 2.11. No fdisk. That wasn't a thing. So....uh.....how were people setting up new disks back in those days without fdisk?
 
I recommend using Norton Utilities 4.5. That is typically the best version to run on XT class computers. Just to be sure you are selecting the right thing - go to Chose Item, then Absolute Sector. The drives it list may not match what dos says, but the last one should be your hard drive. If it does not show that, then your BIOS failed to see the hard drive. I would also suggest that you use at least DOS 3.3 or 3.31, unless this machine is not sufficiently IBM PC compatible.

Double check that both cables are connected completely with pin 1 facing the correct direction at both ends.

Were you getting any hard drive controller error (for example, 1701) during boot?

Yea, there is no great way to recover raw bits from an MFM/RLL type hard drive. There is only one tool that I know of, and that only works if the drive is not dead. Also, be aware that moving an MFM/RLL type hard drive (ST506/ST412 interface) between different models of hard drive controllers will usually NOT work. Typically they are only readable by the model that LLFed it.

FDISK was a "thing" in DOS 2.0. It was DOS 1.x that did not support hard drives (although there were a couple of 1.x OEMs that had support added in).
 
Cool machine! You will most likely have to low-level format that drive to bring functionality back. Type “debug” at the DOS prompt; enter “G=C800:5” and that will bring up the format utility built-in to the controller’s ROM. Then you’ll have to enter the parameters for the drive in, and it should format.
 
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