Ltning

@ltning@weirdr.net

He/him. This is one of my alter egos in the retro world. Read about this instance on front page. My goal is to be able to post here from a 286* running DOS. Might be a while..

and enthusiast with a craving for retro (mostly PC) hardware. Four kids and a wonderful patchwork family.

*Speaking of 286es: http://floppy.museum/

25 following, 49 followers

7 ★ 5 ↺

Ltning »
@ltning@weirdr.net

Baking my next project, a thread...
[Edit - fixed attachment]

I've said somewhere I want to run NetBSD on a . Now obviously that's not actually possible, but I should be able to do the next best thing - run it on a 286 upgraded to a 486SLC!

But wait, most 286es only support 4MB RAM, although the ol' chum of a chip supports a whopping 16MB. So I have to find a motherboard that can do this.

Thing is, I already have one. See picture. But it's currently occupied doing very important Enterprisy stuff - it runs IBM OS/2 1.3 Extended Edition..but at least I know what I need!

otherboard with a soldered 20MHz 286 CPU and a Citygate chipset.

Alt...otherboard with a soldered 20MHz 286 CPU and a Citygate chipset.

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    3 ★ 0 ↺

    Ltning »
    @ltning@weirdr.net

    So as usual, its eBay to the rescue. Found a board just like it, except there's good news and bad news: the good news is the CPU is socketed on this one, making the upgrade job a lot easier.

    The bad news? See picture.

    Zoomed-in picture of the new mainboard, showing green gunk on the board itself and in the RAM sockets. Yuck!

    Alt...Zoomed-in picture of the new mainboard, showing green gunk on the board itself and in the RAM sockets. Yuck!

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      1 ★ 0 ↺

      Ltning »
      @ltning@weirdr.net

      I'm a bit of a n00b at this, but I have salvaged a couple of boards before using vinegar and a toothbrush, so I'm trying my luck with that. After applying the vinegar and watching, hearing and smelling it sizzling, I dunk the affected part thoroughly for a few minutes...

      Kitchen paper dunked in 12% vinegar, placed on the affected part of the motherboard to allow the vinegar to do its magic without disappearing into thin air.

      Alt...Kitchen paper dunked in 12% vinegar, placed on the affected part of the motherboard to allow the vinegar to do its magic without disappearing into thin air.

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        4 ★ 1 ↺
        Network == Abstraction Layer boosted

        Ltning »
        @ltning@weirdr.net

        And I know one should not apply regular water to electronics, but I'm trusting Oslo Waterworks to supply me with nice, clean water from the tap. It comes at high pressure to boot, so I can quickly get rid of all the vinegar to prevent it from slowly eating through everything. As long as I dry it properly and quickly, it should be fine, I'm told.

        I said I was baking - It was not a randomly chosen term.

        The mainboard is literally in the oven! 60 degrees Celcius in hot air-mode for, say, an hour or so should do, I guess.

        Alt...The mainboard is literally in the oven! 60 degrees Celcius in hot air-mode for, say, an hour or so should do, I guess.

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          3 ★ 1 ↺
          Network == Abstraction Layer boosted

          Ltning »
          @ltning@weirdr.net

          And it lives! Apparently I'm officially operating a Motherboard Bakery! :)
          Now I need to get it properly configured and tested with DOS, then I can move on to the next steps - which involve the CPU upgrade, and assuming that works, creating actual, physical floppies.

          (In other news, the instance on this poor Pentium Pro server is sweating hard whenever I post something. So let me know at @ltning@anduin.net if you have problems receiving/reading my posts. I've made some tweaks but it will be unavoidably detained for a while following each post, my apologies for that..)


          Picture of BIOS during boot. It's a 1990 American Megatrends BIOS, for the TD60C board, BIOS version 2.42B. It shows a 20MHz CPU clock and 15872 KB RAM tested OK.

          Alt...Picture of BIOS during boot. It's a 1990 American Megatrends BIOS, for the TD60C board, BIOS version 2.42B. It shows a 20MHz CPU clock and 15872 KB RAM tested OK.

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            2 ★ 1 ↺
            Headbanger75 boosted

            Ltning »
            @ltning@weirdr.net

            Herewith, the actual machine. Some specs ..
            - Motherboard: Zida TD60C
            - CPU: Harris 286 28MHz
            - RAM: 16MB "RainbowRAM", 55ns (check out the LEDs!)
            - Graphics: Cirrus Logic CL-GD5422, 1MB
            - Network: 3com EtherLink III (3c509)
            - Floppy: 2-in-1 90mm (3.5") and 1.2" floppy drive
            - Storage: Promise DC200M caching IDE controller, 2.5MB cache
            - SCSI: Sound Blaster 16 SCSI :D


            Dark-ish picture showing motherboard mounted horizontally on a transparent acrylic surface. Underneath a combined 5.25 inch and 90mm floppy drive. The installed RAM lights up in different colours, four sticks with blue, purpole organge and yellow LEDs, respectively. VGA, network and sound cards are also visible.

            Alt...Dark-ish picture showing motherboard mounted horizontally on a transparent acrylic surface. Underneath a combined 5.25 inch and 90mm floppy drive. The installed RAM lights up in different colours, four sticks with blue, purpole organge and yellow LEDs, respectively. VGA, network and sound cards are also visible.

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              Network == Abstraction Layer »
              @overunderlay@bsd.network

              @ltning any 286 over 16mhz is a unicorn!
              Great find!

                2 ★ 0 ↺

                Ltning »
                @ltning@weirdr.net

                Well .. that went sideways. Despite many attempts, I have yet to find a 286 - or a 386sx for that matter - that will boot the NetBSD floppies without failing in some way or other. I'm not yet certain (perhaps someone here knows?), but there may be instructions missing from the various 486SLC and 486DLC CPU variants that my ugprade modules have. Or there are other bugs that I have not been able to figure out.

                Anyway, I've reduced my ambitions ever so slightly, and am now in the process of installing NetBSD (-CURRENT) on what is essentially a 386SX-class machine: 16-bit bus, 24-bit addressing, 16MB RAM, and nearly as unpleasantly slow as the 286 I had planned to use. It is however equipped with an IBM-branded 486SLC, which is from the Blue Lightning series. This one definitely has a full 486 instruction set. More hardware details will follow when I've completed the build (and installation).

                Meanwhile, the obligatory screenshot from the installer. Note the ETA for simply unpacking base.tgz ..

                Screenshot from installer. Shows base.txz being extracted, at a speed of 110 KB/s. ETA given is about 30 minutes, which turned out to be relatively accurate.

                Alt...Screenshot from installer. Shows base.txz being extracted, at a speed of 110 KB/s. ETA given is about 30 minutes, which turned out to be relatively accurate.

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