Repair Log: PC Chips 486 motherboard, unknown model \ VOGONS

Repair Log: PC Chips 486 motherboard, unknown model

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First post, by Eep386

Posted on 2021-09-10, 07:44

Eep386 Offline

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Joined: 2012-09-14, 05:25
Location: Not far from Sacramento, CA

Got this PC CHIPS motherboard today in the mail. Seller claimed it was totally dead, no POST codes on a diagnostic card.
Nothing seemed wrong at all upon visual inspection until I tried moving some of the pins on the CHIP 6 and CHIP 7 labeled ASICs, and found a large number of lifted pins.
Reflowed the pins, and got a successful POST on the first try. 😁

PC CHIPS boards, in my experience, seem to love growing loose pins. Guess their wave soldering equipment ran too cold or something back in the day.
It's still not yet 100% finished as some of the pins on the SIMM slots are a little rusty, but this is encouraging progress at least.

The whole board:

Detail on the ASICs, maybe you can just barely make out the resoldered pins:

Rev: 2

The BIOS:

Filename: PC CHIPS unknown 486 Board.zip
File size: 36.82 KiB
Downloads: 24 downloads
File license: Fair use/fair dealing exception

Life isn't long enough to re-enable every hidden option in every BIOS on every board... 🙁

Reply 1 of 3, by computerguy08

Posted on 2021-09-10, 11:13

computerguy08 Offline

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Joined: 2019-02-02, 16:40

This is a really cool find!
There is nothing like it in UH19 yet, but based on the BIOS image you attached, I was told its a UMC 480 clone.

Will be digging more for info.

Reply 2 of 3, by Eep386

Posted on 2021-09-10, 15:50

Eep386 Offline

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Rank: Member
Posts: 459
Joined: 2012-09-14, 05:25
Location: Not far from Sacramento, CA

If I had to wildly guess, I'd claim that the board looks like a close sibling of the M-407. It could be an older revision M-407, but I have no real way of knowing for sure.

Life isn't long enough to re-enable every hidden option in every BIOS on every board... 🙁

Reply 3 of 3, by Eep386

Posted on 2021-09-10, 18:22

Eep386 Offline

Rank Member

Rank: Member
Posts: 459
Joined: 2012-09-14, 05:25
Location: Not far from Sacramento, CA

Following up, I tried the MR BIOSes for the UMC 48x, and they don't work with this board, so I don't think it's a relabeled UMC chipset. Four to one odds, it's probably one of PC CHIPS' funky "Sarc" chipsets.

HOLD THE BOAT! An OPTi 491 MR BIOS displays the POST test and allows me to enter CMOS setup, but it's obviously not the right BIOS as it throws a bunch of errors about RAM and the cache. I'll try a different flavor of OPTi 48x/49x MR BIOS...

Further update: Can't quite get any of the OPTi 49x or 48x MR BIOSes to work 100% with it.

Life isn't long enough to re-enable every hidden option in every BIOS on every board... 🙁

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