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My XT-286 (WIP)


Apr 8, 2019
Hello everyone!
This is my work in progress latest build. Using a "Weird? rare?" motherboard made by OCTEK (PN 890102. XT-286 Rev 1.1)
It's a 286 10mhz, but with only 8bit isa, and very close to the known XT JUKO clone motherboard. No fake marketing like IBM XT-286 16bit :)
No 80287 socket. 1016kb RAM (BIOS are stealing 8kb). 8 Dip Switch, like an XT standard.
At 10mhz it's kill my JUKO Clone at 15mhz...

Inside my full tower:
1.2mb and 1.44mb Floppy
4GB Scsi HD
Plextor SCSI CD
Multi ide-floppy-serial controller 16bit.
VGA Cirrus Logic 5402 (Acumos AVGA2) 16 bit.
Disk On Chip (8MB with DOS and SCSI drivers) & RTC (smbaker) 8bit.
Fan Slot blower
Trantor 130b SCSI w/bios 8bit (Can boot directly from any SCSI devices, like Bernoulli, Jaz, ZIP. (and SCSI HD 2gb max)
MDA graphics (Used for 32kb of DOS high memory) 8 bit.
Smc Network card (Mainly used for XT-IDE bios) 8 bit. XT-IDE Bios still needed for "hook" to Disk On Chip boot
Sound Blaster 16 CT2980. 16 bit.

Good: Can run programs that needs 286 CPU instructions. (Like Monkey Island 2). Still looks like an XT :)

Bad: 99% XT compatible. HD Floppys with 2M-Xbios doesn't work (And 2m-ABIOS neither...).
Even with 2M-Xbios source code, I need to see how both bios interact...and maybe with help, fix that issue.
Some problems with software using autodetect routines. Some programs shows AT Machine... others XT Machine...
CPU a little hot...will glue a small cooler/fan

WIP VIDEO. Hard Disk already fixed :)

Now, some pictures. !!!




Apr 8, 2019
Hi @ozzyrules it would be great if you could read (dump) and share your motherboard's BIOS, either by reading it directly in an EPROM reader or using DOS' debug command

Sure. Attached Xt-286 v3.28. Date 08/25/89 from OCTEK motherboard.
I've tested it on PCEM 17. It boots using a "JUKO PC CLONE" machine.

I didn't find much information about this motherboard. Only this similar:
Motherboard: Hedaka HED-919 (Bios Dated) v3.28 12/22/89
This one was added to 86BOX emulator in some versions, then removed (because of lack of chipset documentation)
PD: I need to test this bios, it seems to be some months newer and of course, compatible.



  • xt286-328.zip
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