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identify 486 motherboard

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First post, by sergiovw1500

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Hi I have this 486 and I need the jumper settings, and bios, because it won´t boot up, I look everywhere and found nothing.

please help me

486.jpgsubir imagen

Last edited by sergiovw1500 on 2016-11-07, 04:05. Edited 1 time in total.

Reply 2 of 49, by keenmaster486

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Try posting your image here: https://postimage.org/
This works better than putting it on some private account like it appears you have done.

World's foremost 486 enjoyer.

Reply 6 of 49, by dondiego

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I've just sold an identical or very similar board. Look at the back, mine was an unidentified PCI486 V1-HJ3 so no manual. Probably came with a DX4 so try with one of those, at least voltage configuration is written on the pcb. By the way crappy late board with fake cache but at least the chipset was fast.

LZDoom, ZDoom32, ZDoom LE
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Romero's Heresy II (Heretic)

Reply 7 of 49, by Paadam

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I have exact same board too, works with pretty much any 486 CPU. You sure about the fake cache?

Many 3Dfx and Pentium III-S stuff.
My amibay FS thread: www.amibay.com/showthread.php?88030-Man ... -370-dual)

Reply 8 of 49, by dondiego

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Yes but performance is good anyway. Mine had even DCA written on cache 'chips', for sure not an Octek board. Bios showed the typical 'write back enabled' message but no cache amount in the summary. To change cpu you need to configure a lot of jumpers.

LZDoom, ZDoom32, ZDoom LE
RUDE (Doom)
Romero's Heresy II (Heretic)

Reply 9 of 49, by kanecvr

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Those don't look like fake cache chips (the ones in the picture). Most fake chips are soldered on, not socketed, and the have something silly written on them like "write back" or simply "cache". Those really look like genuine cache chips. I have a couple of early 486 boards that came with the same cache chips and they work fine (tested with cachecheck and speedsys).

Reply 11 of 49, by Paadam

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Mine are socketed and I used them on another board also to test them, worked fine.

Many 3Dfx and Pentium III-S stuff.
My amibay FS thread: www.amibay.com/showthread.php?88030-Man ... -370-dual)

Reply 14 of 49, by quicknick

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Unknown V1-HJ3.jpg
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Got this board a few days ago, without a CPU. It was very dirty, and after cleaning it I installed a intel 486DX-33 and powered it. Nothing, just some low pitched sound from the speaker. Tried also with other CPUs, up to Am5x86-133, setting the voltage accordingly (the only jumpers documented on board are the voltage ones). No luck with any CPU. After close examination, turns out almost half the pins of the northbridge had cracked solder joints. So after reflowing them the board came to life, and it POSTed with a few CPUs that I have around.

I was able to boot into DOS and run some tests with i486DX-33 and Am486DX4-100NV8T, but others such as Cyrix DX2-66, Am486DX4-100SV8B and the Am5x86-133 just hang at the "WAIT..." message, with A2 code on the POST card. Lacking the manual/jumper settings, I believe it's next to impossible to set the board for one of these processors.

Another issue is the L2 cache - it simply doesn't exist, according to Speedsys and Cachechk, although the BIOS reports "Write Back On" at boot time (but no amount of cache), and there is no enable/disable setting for external cache in the BIOS, only a few timing options. I've also tried the board with two BIOS chips (version 2.1 and 2.3) from the dead EXP8449 board that I have. The board seemed to work fine with the "foreign" BIOS, there was a setting for external cache, but the programs still wouldn't detect any. The SRAM chips are working, tested on the TL866. I also shuffled them around, nothing happened. Any ideas?

Here's the BIOS dump, if anyone should need it in the future:

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BTW, original poster's photo is still available if you replace "postimg" with "postimage" in the URL.
Or this: https://postimg.cc/8j1tcMyr

Last edited by quicknick on 2019-02-13, 22:39. Edited 1 time in total.

Reply 15 of 49, by prmcrs

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Hi quicknick, could you please specify what model of EEPROM can use to replace mine?

My board came with corrupted BIOS and I need to re-flash it, but turn out that it's non-erasable, so I need to buy a new chip.

Reply 16 of 49, by Intel486dx33

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I have the same motherboard. It is a really good motherboard. I have mine with an AMD 5x86-P75 CPU over clock to 166mhz. I just had to set the jumpers to 4x40mhz. Left the voltage alone. No other tweaking required.

It a ( M918i PCchips ).

See my posts:
AMD 5x86@160mhz., Media Vision PAS16. ( Win 95 )

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Reply 17 of 49, by quicknick

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@prmcrs: My board has a 27C010 EPROM (UV-erasable), don't know the manufacturer as I didn't remove the sticker. In theory a Flash memory like SST27SF010 should work as well, but I haven't tested. Please, if your board came with a CPU installed, post a picture that shows the jumper positions for that particular CPU.

@Intel486dx33: the hope that you gave me was short-lived. Although pretty similar, the boards are not the same. Notice number of SIMM slots, placement of cache chips and jumpers... So, still no idea about this board's jumper settings.

Reply 18 of 49, by prmcrs

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@Intel486dx33 thanks for your help, but like quicknick says, the motherboard is different 😢

@quicknick thanks for the data, i will try to flash your binary dump in a new 27C010 chip. Here in Argentina I don't know if I will be able to find the model SST27SF010. Do you know any equivalent other?

Reply 19 of 49, by bellarmine

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Hi,

Thought I'd try my $0.02. Old story for me finding the model, found an old 486 back in 1999 and had 486C-V2 on it. Turned out to be A-Trend, was near my 2nd PC (after a 386!), had a lot of fun with it.

Try this site:
http://www.elhvb.com/webhq/
Click on "Motherboard Database", follow the steps to narrow it down by your slots (3PCI 4 ISA), and you can browse though about two dozen of them.

Or try using your BIOS string as they suggest, might give you a brand at least.

For the real Cat's Meow, my favorite, go here:
Total Hardware 99 - 1000's of MBs, HDD, Video cards, you name it:
https://th99.bl4ckb0x.de/

Look under "motherboards" > 486, and click the two pages: picsA-H | picsI-Z
This way you can browse by image. Should take you about 15 minutes to browse it. Just pick something to scan, like the row of cache sockets, or the two SIMM sockets (uncommon).

You can even download this HANDY vintage repository by the links at the top of the page (ASCII or GIF IMAGE Versions). Still my favorite vintage resource.

I looked through it myself quickly, unfortunately couldn't find a match - maybe you'll catch something I missed. Any numbers at all on the BACK of the board?

Hope this helps, cheers! Bellarmine

When working on a job, you have 3 criteria: Fast, Good, and Cheap (i.e., Quick, High Quality, and Low Cost). Only 2 out of 3 are practical.