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486 eisa

What a monster. Looks like you're going to need a few chips to get it going. It appears to be missing two dallas chips, the keyboard controller, and possibly the BIOS.
 
I have one of those DALLAS chips for sure, didn't notice it was missing the other stuff. BIOS might be hard to locate, keyboard controllers probably not. The cache and support chips seem to be there.

For the money figured why not.

I found the manual online, BIOS chip is a 28-pin, 27512 chip, with a 200 ns access time.
 
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You sir are braver than I. The manual pictured isn't for the motherboard (go figure). Some digging on archive.org might turn up a BIOS image and EISA tools/config. Nice to see the guy finally dropped the price, it was something ridiculous before considering it was missing important chips.
 
I found the manual online, also found the configuration files. I have BIOS for MBE486 but that one auto configures memory, different board. So I need to find the correct BIOS and get it burned. I knew the manual he showed wasn't for the board he was selling. Mylex isn't archive because of spiders.txt.

Anybody here happen to have that same motherboard?
 
I was wondering who won that auction :)

I was debating... and debating... and debating! But I've two 486 boards that I've picked up within the last 6 months that I've not yet had a chance to mess with.

Glad that it found a good home!
 
I have a ton of 486 boards, but one 2 are EISA (well 3 if this shows up). If I find a cheap deal I snag it.
 
Back in the day (1991-92ish) when I worked at Zeos, we used to put that motherboard in the ultra high-end servers we'd put together. They were so specialized from the commodity 386-sx16's we were building that the Mylex 486's were put together in a special area and only the crew with the best knowledge and experience were allowed to work on.

You may be able to find the EISA config utility and/or other info on that board here:
http://www.mpcdrivers.com/file_lib/zeosbbs/zeosbbs.html

I always loved that board- wished I had one back then. Actually, it's still sorta on my secret wish list.
 
The early 486 boards were cool just because of all the support chips they used, and just because of the size. Way back before everything was simplified down to a single chip.
 
Board came in today, looks new.

4 missing chips DS1225, 8742, 27512, DS12887. The DS12287 I have, the DS1225 I can source from ebay. The 8742 should be a keyboard controller, are they pretty much all the same from that period (I have one from AMI in stock). The 27512 is the BIOS chip, still looking for that. Installed an Intel 486/66 overdrive and 30 pin RAM I have so just need to find the BIOS and get the last few chips.
 
Are you sure these chips are required and not optional? It seems kind of weird for the board to be like-new with everything else OK and someone to have removed 4 chips. I'd give it a try if it powers on if I were you.
 
Without a BIOS this board is dead. The Dallas chips just keep configuration data intact (one for the CMOS and the other for the EISA config). Keyboard controller is needed to do anything.

I figured somebody had this unit as a spare and gutted it when they needed parts for an in use machine. Luckily everything gone is socketed so no soldering is required.
 
Hello,

I've been reading this forum for years, learned tons of interesting tips and useful informations. Big thanks for all.

And now, i think i can help you, if you're a bit patient (i have lot of work ahead at the moment.)

I have got the same board, i noticed this one on eBay and was about to buy it more than once. Never did it.
I've got the BIOS on my board and tomorrow or this week-end, as soon as i've got a spare time, i will copy it, take pictures of the chips and the board. I hope it will help you, as much as you all guys helped me in the past.

Cheers from Reunion Island
 
To some degree I think. Though keyboard controllers are sometimes customised by the manufacturer to add special key combinations (like CTRL +/- for turbo select).
 
Well 2 eproms are on the way (if I need a spare), using an old AMI keyboard controller 92 vintage, and the other Dallas chip is on the way. So I will just need the BIOS and hope my junky eprom burner works.
 
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