486 VLB upgrade to MicroLab Case

I was unsuccessful with the MicroLab 286 motherboard. But I tested putting this 486 VLB motherboard in the MicroLab case and it will fit. So, I am going to put this 486 in the MicroLab case.

I got this 486 at PT Surplus. It came in a full tower, 25” high. I don’t need such a big case so I am going to clean it up and put it in the smaller MicroLab desktop case. This motherboard is a VLB type and has five ISA slots and three VLB slots. It came with several cards, but no sound card. The cards are a CD-ROM interface, Modem, I/O card, Floppy and Hard Drive controller (VLB) and a video card (VLB). There are two IDE hard drives, one CD-ROM, a 3.5” floppy drive and a 5.25” floppy drive.

I removed the motherboard from the case. It is a little dirty but there is not any corrosion. It uses a CR2032 battery. The CPU heat sink and fan are the dirtiest. There are two SIMMS installed and there are two slots open (total of four slots). The keyboard is a 5-pin DIN type.

I will take the power supply out and clean it up and use it in the new case. The old MicroLab power supply still works and can be stored for future use. [I may use the MicroLab power supply. They look very much the same but I think the one in the MicroLab case may be better. It is 200 Watts. I did end up using the MicroLab supply. The power supply that came in the large tower case is not working]. The MicroLab case has three external 5.25” bays and one 3.5” external bay. There is room for another hard drive under the power supply. But I think I will stay with one floppy, one hard drive, and one CD-ROM. [I ended up using both floppy drives].

7/10/22

I tried powering on with the MicroLab power supply and I got mixed results. Once or twice I did get a front power LED and the small fan on the CPU heatsink “bumped” and stalled. I got no screen readout. I decided to try the original power supply that came in the huge tower. That gave me nothing. I then tried the power supply from the VIP 200 286. It worked! The screen came on and the memory counted down but then I got an error saying the keyboard was missing.

I thought the power supply from the MicroLab 286 was working but now I am not sure. I am going to try it again just to confirm if it does the same thing. I was able to figure out why the keyboard was not working (in line fuse on MB) and I temporarily bypassed the fuse with a jumper wire. I also took out the disk controller card before I booted. I want to try the MicroLab power supply with this configuration before I label it bad.

I swapped in the MicroLab power supply and it worked. It may have been disabled by the bad keyboard fuse. Or maybe it was not firmly connected at the wire connectors. At any rate it seems like the MicroLab power supply will work.

Now I need to solder in a fuse for the keyboard on the motherboard. In the meantime I will put in the other cards and drives and see what else is working or not working with this machine.

I put in the drive controller card (VLB Card) and hooked up the 3.5” floppy and the two IDE drives that were in the case. One of the hard drives could not be detected and had a knocking sound. I unplugged it and only had the one HD attached. I can detect a drive in the BIOS and set it to a 520MB drive. But on boot I get a Hard Drive failure and then I hit F1. After hitting F1 I get a boot of MS-DOS 6.22 and it asks for the date and time. The date and time are correct and just hit enter on both. This brings me to a C:\> prompt. When I put in the DIR command all I get is the command.com. VER reports MS-DOS 6.22.

So, apparently the hard drive has a MS-DOS 6.22 boot but there is nothing else. There are no DOS or Windows files. (The Windows files are probably on the other drive that is not working?)

Why do I get a message saying HD failure but still get a boot to DOS off of the same drive? (See below, I had the wrong drive parameters).

The BIOS shows ram as 32Mb and CPU Type DX4-S at 100Mhz. Two serial ports and one parallel port.

I changed the BIOS to boot first from A: After reboot I got the hard drive fail error (20) and then hit F1. The floppy tries to read the boot disk but it does not read. The floppy drive light is on and the cursor is blinking on screen. But it is not booting. The floppy drive does not sound good. It seems to be spinning but not reading. Maybe try the cleaning diskette? I was able to get a directory when booted in MS-DOS 6.22 and I ran Checkit from this floppy drive. So it is at least working a little. Just not booting.

I connected the 5.25” drive as the B: drive. I was able to read several 1.2M diskettes, and the IBM PC-DOS 3.3 diskette, which I think is a 360k diskette. Then I reset the A: drive to 3.5” 720k and set the boot to “A, C” and rebooted. I got the usual hard disk fail (20) message and this time I got the Floppy disk fail (40) message. I put in a DOS 5.0 boot disk formatted as 720k. Then I hit F1. It failed to recognize the disk and asked to supply another disk. I put in the 1.44M DOS 5.0 boot disk and hit enter. The computer booted from the MS-DOS 6.22 on the hard drive.

Now I will try to use the 5.25” floppy to boot, as A:. Reset BIOS to A: as 1.2 and B: as none. Put in a DOS 5.0 boot disk in the 1.2M drive A: and reboot. Hard disk fail (20) but no other error. Hit F1. This time the computer booted from the floppy.

Both floppy drives seem to work but I can’t boot off the 3.5”. I can boot off the 5.25”.

Maybe there is a setting on the disk controller card?

(I did notice that the floppy disk loaded faster after I correctly set the hard drive and no longer got the hard disk failure error. Maybe the floppies will work better now?)

And when I used FDISK from the DOS 5.0 boot the program seems to look for a second drive, even though it is not present in the BIOS. The partition table? [I had the second hard drive entered as “user” but no parameters. When I set it to “None” it no longer looked for second drive]. 

Maybe try another hard drive and format with DOS 5.0? Not sure yet if I want to destroy these two drives that came in the case yet. 

Anyway, I do seem to have a working computer here. I need to solder a wire for the fuse bypass, or get another fuse. Then I can put it back in the MicroLab case with one or two floppy drive(s), one hard drive, and one CD-ROM. There is no sound card so will have to use the CD-ROM audio only. Also will need a serial mouse.

I ended up soldering in a jumper wire over the fuse for the keyboard. I just need to remember to not unplug or plug in a keyboard with the power on.

I reassembled the motherboard in the case, power supply, VLB video card, VLB Multi i/o and Drive Controller, and the ISA CD-ROM controller. I also attached the wires for the front panel. I power it on and the fans came on and the keyboard lit up but there was no video. I turned it off and removed the ISA CD-ROM card and powered on again. Same thing. I unplugged the front panel wires then rebooted. That worked. I now got the video screen with the familiar hard disk failure (80).

I tried another hard drive, the one from the NEC 286. It also failed and could not be found with FDISK. I removed the original hard drive and looked up the specs on the Internet. It turns out I had the drive parameters wrong. I used the parameters I found for the drive and rebooted. This time I did not get the hard drive fail error and it booted with MS-DOS 6.22. I rebooted from floppy to DOS 5.0 and then ran FDISK and deleted the partitions and created a new partition. I got a warning from the BIOS but after I confirmed I was able to finish the partition and reboot. After reboot I checked the disk with FDISK again and it looked good this time.

I ran a format on the C: drive. It is running now and there are several recovery messages but it is moving forward, slowly. The message is “Trying to recover allocation unit nnnnn.” Apparently this drive had crashed and there are several sectors needing attention. Hopefully it will finish formatting and then I will install DOS 5.0 onto the hard drive.

The format finished. I reset the 3.5” 1.44M drive as the A: drive and rebooted with the MS-DOS 5.0 diskette. It booted and I installed DOS 5.0 to the hard drive. I rechecked the BIOS and set the floppy drives to A:=1.44M/3.5” and B:=1.2M/5.25” and set to boot A,C. Rebooted and tested all drives. Everything is working. The floppy drives are booting now. Apparently the hard drive settings were affecting the floppy boot. Now that it is correct it is all working. I started Checkit and am running a test on the Hard drive. 

Next will be to install Windows and a Mouse and the CD-ROM driver. Finally, I need to clean up the faces of the drives. Then I can re-assemble the case enclosure and this machine will be done. 

This will be my fourth 486 in my collection - and the highest specs for the processor itself. This is now my “MicroLab 486”, taking the place of the former MicroLab 286.

I wonder if this case will be a problem for the 486DX4-100 and heat. The original tower case had a lot more room. Plus the fan on the heatsink seems to not spin sometimes. I may have to add a cooling fan, or try another case. Let’s see how this goes.

 VIP 200 - 286

I purchased this computer for my parents when they were living in Seattle and I was visiting them, while I was now living in upstate NY. I found the best deal I could using Computer Shopper and had the stuff shipped directly to their address. When I arrived for my visit I set it all up for them and showed them how to use it. This was their first PC at home. I would call in using Carbon Copy and help them learn how to use DOS and software programs like WordStar. At home I was using the AST Premium 486-33 that was given to me by a member of the Hudson Valley Computer User’s Group. At that time I was using DOS only and a dial-up modem.

I ordered this computer with a VGA White screen and standard VGA 8-bit ISA interface card. It also came with parallel and serial ports. It has a standard AT keyboard and connects with the built in 5-pin DIN keyboard connector off the motherboard and extended to the front with an interior extension cable [now has a broken wire. Now just plugging keyboard into back port]. There is a PC speaker but no sound card. It included a 3.5” floppy disk drive. I can’t remember if we added a hard drive on the order or not. Probably. I don’t remember setting up a dual floppy system. I think it was DOS 5.0 on an IDE hard drive. It probably used an ISA multi-I/O card for the floppy, HD, and serial and parallel ports. I set up a modem also.

After my parents no longer used this computer I put this computer in storage, for quite awhile. At some point after I started getting interested in retro computers I got it out and I noticed that the barrel battery was leaking. I removed everything from the case and then removed the battery and cleaned it up with vinegar and isopropyl alcohol. It has been disassembled ever since and the cards and drives have all been used elsewhere. I don’t have an exact record of what cards and drives were in this machine.

Recently, while trying to clean up the MicroLab 286 I also got out this VIP motherboard and noticed it still had some green residue and needed more cleaning. I have been cleaning it for a few days along with the MB from the MicroLab. After I failed to get the MicroLab MB working I decided to try powering up this VIP MB to see if it still worked. It does! I am still cleaning it but it does power on and I can get into the BIOS. After this test I decided to switch from the MicroLab 286 to this VIP 286. I am now cleaning up the case and gathering the cards and drives I will need to put it back together. I am using the 3.5” floppy and 3.5” IDE HD from the MicroLab along with the drive controller card and a separate serial and parallel card. The VGA card was in my drawer. It may be the very VGA card that was in this computer, I don’t know. But it is my last ISA VGA card I have available. (It was the VGA card from the PC Partner 386sx. I have since put it back in that computer. But I do have a couple CGA cards).

I took the power supply out of the case and blew out the dust. Then I cleaned up some corrosion on the case itself. Next is to replace the power supply in the case and test it for proper voltage. At the same time I continue to clean the motherboard. I have made progress in removing the green by laying some cotton swabs soaked in vinegar and then brushing with a stiff bristle toothbrush. It is getting better. After it is clean I will finish reassembling the motherboard, cards, and drives.

I have been using the VGA white screen on the IBM XT-286 but now that I have this VIP 286 going back together I will trade it back to this computer and put the IBM VGA color monitor on the XT-286. (Don’t have the VGA card available. Will use the VGA White on the NEC 286 - Update: I put the VGA card back in the VIP 200 and am ready to use the original VGA White screen with this VIP computer).

I finished cleaning the motherboard and then I reassembled the case, power supply, and the motherboard and VGA card. I powered it up and I do get a screen report and am able to get into the CMOS Setup. But I cannot get a floppy drive to be recognized.

I used the floppy controller from the MicroLab 286 but I can’t get the floppy to work. I tried moving the card to different ISA ports. No difference. I have a Winbond Multi-I/O card and I tried that. I still can’t get the floppy to boot. But I did once get the light on the floppy to come on. So, far I am getting mostly CMOS errors about the floppy controller failing.

I wonder if I will get better results if I first install a backup battery? I need to get a battery tray and attach it to the header on the motherboard and then set it up to use the external battery. I am out of those AA battery trays so I need to order some more. Maybe I have one in another computer I can use temporarily. If after I use the external CMOS battery the floppy controller still fails I will need to look for another controller card. It’s a little odd that both of these controller cards are bad but they are old, so it could be that they are both bad.

I found a four-AA battery tray in one of my drawers. I will try to find a patch cord that will fit the header on the motherboard.

I attached the CMOS external battery. I got a message that said the CMOS battery was low. But after a reboot I no longer get the CMOS battery error. I only found some used AA batteries. Maybe if I put in fresh new batteries it will work better. Anyway, the CMOS battery error is not coming on screen. 

I’ve been getting one long beep followed by three shorter beeps. The RAM check stops at 512k and then the beeps as noted and then continues to count to 768k. Then the error message includes a CMOS Memory mismatch. I changed the pins on the motherboard to set it to only 512k (JP7 Open, JP8 Closed, JP9 Closed). Now when the memory is tested it stops at 512k and there are no longer any beeps. The CMOS memory error happened one more time but then on reboot it no longer shows the CMOS memory mismatch error. I do still get the floppy controller failure.

I think the ram chips in Bank 1 are bad. The chips in Bank 0 seem to be ok. There are four chips in each bank, for 512k each. So, for now I only have 512k, but at least no memory errors. I will continue to troubleshoot the floppy controller.

I re-tried the Winbond card in each ISA slot. It failed in each slot. I then re-inserted the card from the MicroLab 286 and this time I got the drive light to come on. It attempted to read from the drive but failed to read both a 1.44 and a 720k DOS 5.0 boot disk. The BIOS is set to a 1.44 drive. Let’s try setting it to a 720k drive. No change.

I tried about 6 or 7 3.5” drives and set to both 1.44 and 720k. No disks will read. I do get slightly different errors on screen depending on the disk. DR-DOS seems to be the most different. I also tried two 5.25 drives, in both 1.2 and 360k. No reads.

Maybe I need to set some pins on the controller? All nine drives are bad?

[Note: while setting up the NEC Powermate 286 I installed the 3.5” floppy from the MicroLab 286 and it working fine. So, I think it is bad controllers.]

The card has following identifiers:

Label: FCC ID: H9NCI-90

Label: Unique Q1 92

On board: UN - 1051 Rev E

Hong Kong

50/91

Chip: Acer M5105 A3E 9204 TS6 A20409

I tried hooking up the IDE drive from the MicroLab. It hangs at boot, no screen. If I disconnect it I get the boot screen back. But the floppy will not read a disk. I tried adjusting JP8 and JP10 but there is no difference. When connected the HD light comes on but it will not continue to boot.

I wonder if I will have the same results with these drives and the controller in the Leading Edge Model D? May not work if slots are 8-bit only. I was not able to test the controller on the Model D. It has an integrated floppy controller and I don’t know how to disable it. I did test the 5.25” 1.2 drives and I cannot get them to boot in the Model D either.

Ok, I’ll put this VIP 200 aside for a while. I need to get another floppy controller card that I know is working. Then I need to test the RAM.

I have an unused Mono graphics adapter in my XT/286. I can either move that Mono adapter to this VIP 286 or use it in the XT/286 and take the VGA out and put it in this VIP. That would allow me to put the VGA White on this computer.

I ended up grabbing an Orchid VGA card from the AT&T Pentium MMX and putting it in the PC Partner 386. I took the VGA card that was in the PC Partner and put it in this VIP machine.

 MicroLab 286

For a time I was not able to find out anything about this MicroLab. I thought it was a white box from a local computer shop, like some mom&pop store that serviced local small businesses. But I recently found out that this was a clone brand that was competing with the likes of NEC and Gateway for cheap business computers of the time, about 1989.

This computer was sold by PAN-UNITED CORP. in Edison, NJ. They were basically resellers, like Leading Edge, and the manufacturer was some source in Taiwan. I have not been able to find the actual manufacturer of the motherboard. The label on one of the ISA slots is from March 23, 1990. There were a few articles in PC Magazine in 1989 comparing these machines to other 286 machines.

I think I got this machine at the same time as the NEC Powermate. It may have come from the batch of stuff I got from an old business in Kingston along with some PS/2’s and some printers. I think I powered it up once and the fans did come on so I thought maybe it would work but I set it aside and it has set along with the NEC Powermate for a few years.

I started to work on this machine a couple of weeks ago. I had previously had some success with my old AST 486-33 and the Leading Edge Model D 8088 clone. I had been reading about some 286 projects on VCFED so I decided I would finally start work on this machine. But, unfortunately, I screwed up a few years ago and I did not notice that there was a barrel battery on the motherboard and I failed to remove it. The battery has leaked and there is a lot of corrosion.

I disassembled the drives, cards, connectors and power supply. I cleaned up and tested the power supply and it is working. I removed the motherboard and cleaned the case. Now I will clean the motherboard before I try to reassemble and power up.

I removed the battery and cleaned up the corrosion. It took a lot longer than some other motherboards I have cleaned. The green residue took a long time to remove. And I think there is still some residue in the keyboard connector and a couple of the ISA slots. I cleaned it until the green was gone from the traces and then I tried to power it on.

I attached the power supply, a VGA card and my IBM VGA monitor, and my IBM Model M keyboard. I powered it on - the power supply fan is working but the motherboard is not posting. Nothing. No beeps (note - no beeper on MB and speaker not connected) and no report to video. Is this motherboard dead? Maybe. There was a lot more corrosion than I have worked with before. This board may be beyond my ability to repair.

The motherboard is not completely dead. I attached a speaker to the board and powered it on again. There is a constant three-beep. Still no video but the three-beep continues until I power down. I was hoping for more of a definitive beep code. But at least we’re getting something so I know the board is at least responding to something. I need to try and figure out what the three-beep means and what type of board this is. Maybe I can get some help on VCFED.

The computer came with one 3.5” floppy, one 5.25” floppy, and an IDE 3.5” hard drive. There was no floppy or IDE controller on the motherboard. The drives were connected to an ISA controller card. When I took it apart I noticed that the floppy cables were missing. The IDE cable was connected to the hard drive. There was no video card installed when I started taking this apart for cleaning. I may have removed the video card previously, I can’t remember. The keyboard port is the standard AT 5-pin din connector. I did not get any keyboard or monitor with this computer, just the CPU box.

So, now I have to decide what I am going to do with this machine. When I cleaned up the Leading Edge Model D I thought that maybe I could use the hard drive from this MicoLab in that machine if this machine did not work. Well, it is not working. So, maybe I will do that and use the drives on the Leading Edge Model D.

I also found an unused 486 motherboard in my stack of stuff. I do not know where it came from. But it is not as corroded as the MicroLab 286 MB and I may decide to clean it up and put it in the MicroLab case. The format of the 486 motherboard is very close to the non-working 286 and should fit the case. I think I will at least try to power it up like I did with the 286 and see if it is viable before I decide what to do.

I also found an old 286 motherboard that was stacked with the 486 motherboard. This 286 board was removed from the old VIP computer that I had originally bought for my folks while they were still in Seattle. I purchased this VIP direct from an add in Computer Shopper and got a VGA white monitor along with it. It has since been disassembled and is missing all the drives and video card. The case remains along with the power supply. The battery was leaking so I removed the battery, a long time ago, and attempted to clean it up. I have not attempted to power it up since. There was still some green residue so I was attempting to clean it again while I was working on this MicroLab motherboard.

I decided to try and power it up while I had everything still setup from the tests with the MicroLab motherboard. It works! There is still some green residue but the motherboard is working. I will continue to try and clean this board. Maybe I will put that VIP machine back together and use the drives from this MicroLab in that VIP computer. The VIP case is a mini-tower and I do not have any other mini-towers with any 286/386/486 machines. The next mini-tower I have is for the AT&T Pentium 200MMX. So, it might be cool to use the VIP mini-tower for a 286 and use the MicroLab case for something else, like the 486?

Before breaking down I hooked up the 486 motherboard and powered it on. I had attached the same speaker that I attached to the previous 286 board. But when I turned it on I got no beeps. And no video. When I turned it off I saw a red led on the board blink. It lit up and then went off again. But otherwise no response from the board. It looks like I have some work to do with this board. But it is well identified and I may be able to find some manuals for it. But at least for now this board will not work to resurrect the MicroLab computer. I may go ahead and put it in the case for storage though.

So, it seems that this MicroLab is a bust and I will need to work on the VIP 286 instead. Time to break down the work area and switch over to the VIP.

07/04/22

I was beginning to clean up a different 486 that I got at the surplus, it is in a full tower 25” high. I wondered if the motherboard would fit in another case. I placed it in this MicroLab case and it will fit. So, I am going to upgrade this case to the 486 motherboard. See the other document for more on cleaning up the 486.

7/10/22

This MicroLab 286 has been replaced and is now the “MicroLab 486”.