First post, by aitotat
I recently found a very little Copam U-series (ultra slim) computer. Only information the seller gave was a photo of BIOS post screen and couple of photos of the computer and what came with it. The seller didn’t have a keyboard so the computer was stuck at battery error on the post screen.
The post screen did gave me some hints about the system. There was SHASTA-F mentioned and that was a very good indication that this was a slow 486 system with Headland chipset and likely without motherboard cache. Turned out I was correct at that assumption.
The computer came with all manuals and disks (driver/utility disks, MS-DOS 5 and Finnish version of Windows 3.1). There were manuals and disks for both 386sx variant as well as 486 variant of Copam U-series. On the photos there was part of manual shown with TVGA8900 written on it. I of course assumed there was some 8900 model Trident integrated but that manual was for the 386sx model (it has 8900C). Also the 386sx motherboard manual was shown and that let me to assume this computer was running at 16, 20 or 25 MHz. But I didn’t know that manual was for 386sx.
So when I finally got the computer (I payed 52 euros knowing only what I described above) it was just as small and cute as I hoped it to be. I opened it first before testing it. It has DS1287 RTC with build-in battery and the motherboard did not have support for external battery. The CPU was Intel 486DX 33Mhz. I assumed it would be SX-25 but that guess went wrong, but not too much. The CPU was underclocked to 25 MHz. The motherboard has jumpers to set the clock to 16/20/25 or 33 MHz. I wonder if they installed wrong CPU at the factory or did they set the jumpers wrong.
The motherboard has 2 MB RAM soldered and then there are two 72-pin SIMM slots that came with 4 MB SIMMs. So it had 10 MB total. This is also the maximum what is supported based on the manual. I did try 8 MB SIMMs without luck so the manual is correct. Based on date codes (late 92), the computer came shipped with 10 MB installed.
The only thing that did not have 92 date codes was hard disk. It is 130 MB Seagate with 13.5-93 sticker on but I think on the hard drive PCB there was 3993. Since battery was dead, the BIOS setup defaults to 40 MB drive. So likely the original hard drive was 40 MB. That sounds small for a 486.
The chipset is Headland Shasta and there are no motherboard cache or even empty sockets. Graphics chip is Headland HT216 and based on manual, it is integrated to VLB and benchmarks indicate this as well. There seems to be 1 MB ram for the HT216 but for some reason most detection programs cannot detect the size. Both the motherboard graphics and system RAM are 80 ns. The SIMMs are 70ns.
Power supply is 65W and it has 40 mm fan. It is loud (but not louder than any other old PSU fans) and I’ll replace it eventually. For now I left it as it is. The computer was very clean inside, no dust at all. But there aren’t many holes for the dust to get in. Ventilation must be poor and the CPU didn’t even have heat sink.
Powering the system gave me some problems. First this seems to be very picky about keyboard. I first tried very old one but it usually gave me errors. So did IBM Model M. There were no problem with Keytronic or later IBM keyboard.
I needed to make battery mod for DS1287 because every time I tried to save BIOS settings nothing was saved and I got the battery error again. So it was not possible to boot because all I could do was enter bios setup. This was first time I did the battery mod and it wasn’t hard at all. I’ve been avoiding motherboard with Dallas RTC but I guess now I’d rather take Dallas than leaking battery. I had two too large coin batteries that I accidently once bought. I directly soldered wires to one of those. I’ll get the usual CR2032 battery holder when those larger ones are used.
When I finally got to boot, it turned out that floppy drive was broken! And not only that, two of my spare drives had stopped working so it took a while to fix it. I had one known broken Mitsumi drive that was dirty. I cleaned and lubricated it and got it working. This Mitsumi is likely the quietest floppy drive I’ve had so it is great on a computer that can’t have any 5,25” drives.
I wanted larger and quieter hard drive so I settled to a 20 GB Maxtor. It is not quiet at all but I didn’t have anything more suitable at the moment so I’ll keep this temporarily. The BIOS does not support drives over 512 MB, as expected from 1992 BIOS. I could have used some drive overlay software but instead I installed XT-CF. This way I can have XTIDE Universal BIOS and CF slot at the back of computer to easily transfer data. This computer does not have any optical drive that could have been used for that.
Now, with case still open but computer functional, is a good time to do some benchmarks. I decided to test every supported clock rates starting from 16 MHz to 33 MHz and then with 486DX2 50 MHz and 66 MHz (way too late I realized I should have also tested DX2-33 and DX2-40, well maybe some other time).
I'm not stopping here. There is a reason why chose that old IBM PS/2 VGA monitor for this computer. And why I decided to keep the CPU underclocked to 25 MHz. More to come.
Edit: Added Speedsys results and reduced picture sizes.