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386 build: A march into the unknown

Discussion in 'Retro & Arcade Worklogs' started by Pierre32, May 22, 2020.

  1. Pierre32

    Pierre32 Member

    Joined:
    Oct 13, 2019
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    Location:
    Sydney
    The Motivation
    I won't lie, I didn't have a 386 build in mind until I found a cool video card for cheap, followed by a mobo. It took on its own momentum from there. And the more I thought about it, the funner it sounded. I have a low end 486 (Presario 425 running an SX/25 CPU), and that can be upgraded, but not much. On the other hand, a proper desktop build gives me a lot more room for activities and experimentation. Exploring the limits of a high end 386 system should be fun. It's also my first time working with a full ISA mobo.

    The Bits:

    Micronica baby AT desktop case
    A very happy newish old stock find, which came in its original box and styrofoam. She's a tank.

    Case.jpg


    Asus ISA-386C
    The first mass production motherboard from Asus. Untested. It came loaded with a 386DX/40 CPU, and an unknown quantity of RAM. I've also picked up an i387DX/16-33 coprocessor. My reading tells me that the clock difference will not present an issue. (Will I even be running software that utilises it? Hush now.)

    ISA-386C motherboard.jpg i387 Coprocessor.PNG

    Goldstar Prime E852 combo controller (IDE, FDD, COM, LPT etc)
    Untested. Handily this has jumper assignments screenprinted on the reverse side, and I believe I have also located a matching data sheet.

    Goldstar Controller.jpg

    For sound, my heart says that my SB16 will ultimately end up in this machine. But before that, I have two problem children to sort out:

    Addonics A151-830 (Yamaha YMF701-S OPL3) sound card
    I've had this running elsewhere, but it's had a bit of an on-off relationship with Yamaha's setup software. For this install I'll be testing the new utility Unisound.

    Yamaha Sound Card.jpg

    Unknown ESS ES688F sound card
    I've had this working fine as a basic Soundblaster clone, but have never found driver software that will talk to it (and have never got the MPU working). I have no manual and no idea what the jumpers are. I think this card just needs a solid afternoon of trial and error - an undertaking that was not tolerable in my Presario's all-in-one case.

    ESS Sound Card.jpg

    I will be driving external MIDI devices too - but we'll cross that bridge when we come to it.

    And here's the little rascal that set the wheels in motion:

    Ipex Tseng ET4000AX video card
    Untested. So it'll be particularly funny if this one's a DOA.

    Tseng Video Card.jpg


    Other assorted necessities pictured below. Neither the CD drive or 5.25 drive are confirmed to be working. Again this build will be a good test bed to determine their status. A parallel port CF card reader will be attached too, to make my life a little easier. If/when all this comes together, I have further plans to push the envelope with this build. But again - when we come to that bridge!

    386bits.PNG
     
    Last edited: May 22, 2020
  2. badmofo

    badmofo Member

    Joined:
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    This is going to be a thing of beauty :thumbup:

    I have that motherboard too - I didn't realise it was a historic Asus. It's a quality product - mine came from a complete machine I surreptitiously snagged at the tip.

    RE that Yamaha sound card - I'll be interested to hear how you go with Unisound but you could also consider this alternate software from Tiido: http://www.tmeeco.eu/TKAYBSC/

    I haven't tried it myself but was meaning to the next time I wanted to try a YMF ISA card - the orginal DOS software package is garbage.
     
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  3. OP
    OP
    Pierre32

    Pierre32 Member

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    Location:
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    Tip finds. You love to hear it.

    Thanks for the Tiido link - I'm amazed I didn't run across that somewhere in all my forum trawling. I will definitely give it a spin too.
     
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    Pierre32

    Pierre32 Member

    Joined:
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    Location:
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    Saturday morning, and the sight, sound and smell of a catastrophic tantalum failure.

    Board install.jpg Cap fail.jpg

    Thankfully not much in the way of collateral damage. And the board does still run, although I suspect it's not wise to push my luck here. I think the row of four ought to be replaced. Thoughts?

    Some positive news though: the video card is good :thumbup:

    POST.jpg BIOS.jpg
     
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  5. adz

    adz Member

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    I'd replace all four "while you're in there" ;)
     
  6. DonutKing

    DonutKing Member

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    Yeah you should probably do the lot.

    It won’t make them immune to popping though. I replaced all the tantalum caps in my old 286 rig and about 12 months later one of them popped again :tired:

    re: maths copro . I’ve had a 387/33 in my 386DX/40 for years and it’s never had a problem. There is precious little that uses it though. I have to disable it for Scorched Earth because the aim/power counters go insanely fast otherwise.
     
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  7. okclock123

    okclock123 Member

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    These are the top 386 components! I love the case, absolutely gorgeous. Saved a photo to my "select old cases" folder. I never used a coprocessor with my 386 back in the day and never noticed the lack of one. Games and office software didn't rely on it at all. You need to find math software from the early 90s to see the advantage.

    What PSU are you using? The original? I'm seriously considering to bite the bullet, buy a USB oscillograph, and teach myself how to test PSUs properly. Every time I did retro power-related things it has always been a pain in the ass. I had exposing capacitors on both motherboards and PSUs themselves on both retro and new. There is this project trying to solve this: https://www.kickstarter.com/projects/doctb/atx2at-smart-converter-protect-your-retro-hardware but I was too late to the party and it's now closed.
     
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    Pierre32

    Pierre32 Member

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    The PSU is a 250W Emacs LP2-4250F. I was originally planning to use a new Seasonic 300W, with a plug adapter cable. But in talking with the seller about case fit, front panel integration etc, he convinced me to go with an included PSU (which basically tripled the price of the case). He couldn't say enough about the build quality. At the very least, I thought, it was a great sales pitch that worked.

    I've only just looked them up, and I guess I didn't spend that much after all. Yikes:

    https://www.pchub.com/emacs-zippy-lp2-4250f-server-power-supply-250w-lp2-4250f-p173482
    https://www.newegg.com/p/2S7-01JA-12UU9
    https://www.aliexpress.com/item/32861136523.html

    So I know I shouldn't be playing with this machine until the caps are done. But yesterday I had the spectre of a slick salesman in my ear saying don't worry mate, you've got the best PSU mankind has ever created. So I did some stuff. I'll settle down now until it's recapped.

    Video output - monochrome mystery
    I'd been doing initial setup with an old Dell LCD, which worked fine. But when I plugged in my Compaq 1024 CRT, it was monochrome only. I verified on another machine that the monitor was fine, and was about to put the call out for tech support when I found this thread: https://www.vogons.org/viewtopic.php?t=53697

    They go into the reasons there, and the suggestions include cutting a trace on the video card (lol no thank you) or more sensibly, creating a short VGA passthrough cable with one pin removed. Then someone mentioned the Trident utility "smonitor" for forcing the card to colour mode, which was the solution for me. It runs in the autoexec which means no pretty BIOS colours for me, on this monitor at least. I'll be interested to test with other CRTs in the future.

    Sound - the hills are partially alive
    I had no luck with Unisound or Tiido's SetYMF detecting my Yamaha card. So I went back over old ground trying different versions of Yamaha's setup software, and the version buried in the DOS folder of this ISO seems to be playing nicely, although I haven't tested MPU functionality yet. Gameport joystick is working.

    I haven't toyed with the ESS card beyond seeing if Unisound recognised it, which it doesn't. But it's not a PnP card anyway, so that was a long shot. As originally planned that will be a trial by jumper - but even then, I believe that all ESS cards require a TSR for MPU functionality. So without drivers, it may see out its life as an FM card only.

    Storage
    - The CD-ROM is good.
    - The ancient HDD is operating fine but sounds vaguely like someone is using an angle grinder in a distant workshop. Will probably go with a CF card down the track.
    - The 3.5 drive is fine. The cranky 5.25 drive is not playing yet. I don't have the right cables at hand to put it back in the chain as the B drive; solution for that on the way. It'll need a service, and maybe some jumper experimentation.
     
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  9. badmofo

    badmofo Member

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    That colour issue sounded familiar - I had a similiar issue with a 386 I put together a while back (8+ years ago it turned out :shock:). That was with a Tseng card too, and I ended up using 'coloron' for what it's worth - same idea I guess.

    RE your Yamaha card - from memory the YMF701 isn't actually PnP. Not sure how that works because there's no jumpers on it but I'm confident it's not, I remember noting that was a useful feature of that chipset once when I was using it alongside another card. That might explain why it didn't work - the 718 and 719 are PnP of course. I never did like the sound of those Yamaha's anyway despite their other fine qualities. ESS is the ticket if you can find the drivers.
     
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  10. OP
    OP
    Pierre32

    Pierre32 Member

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    Hmm good info on the Yamaha card :thumbup: Misleading little guy.
     
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