UMC UM8498F board, no POST \ VOGONS

UMC UM8498F board, no POST

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First post, by magicvoodooable

Posted on 2022-09-24, 22:39

magicvoodooable Offline

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Hi all!
I still struggle to get this (see below link) MoBo to even show any POST code.

https://theretroweb.com/motherboards/s/biosta … 3F-umc498f-2vlb

PSU is good. I checked with another 486 based MoBo and that one boots OK.
I checked CPU voltage and Clock. Both good, 5V and 33MHz. CPUs I'm testing are: Intel 486DX 33 and DX2 66.
I removed all CPU configuration jumpers and tried a few settings I found based on some information I found for Intel DX/2 CPUs ... no difference.
The BIOS should be OK too.

Since there is not too much, actually none, documentation and BIOSes for this MoBo available ... I'm not sure what to do next.

Anyone any advice? Thanks!

Reply 1 of 5, by Horun

Posted on 2022-09-25, 03:06

Horun Offline

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I remember someone on Ebay selling those as untested system pulls. There is a topic here about them somewhere and Yes there was little to no info on them on the internet..
How to identify this 486 motherboard techmedia UMC um8498F Maybe some one there can help you.

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 2 of 5, by weedeewee

Posted on 2022-09-25, 09:42

weedeewee Offline

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Have you tried setting the jumpers according to how they are set on the available photos of the board ?

Thanks for the bios dump you posted here Re: Trying to set up my first DX4-100 ever and encountering strangness?

@Deksor
The bios for https://theretroweb.com/motherboards/s/biosta … 3F-umc498f-2vlb is,
as noted in Re: Trying to set up my first DX4-100 ever and encountering strangness? ,
only 64K and is missing the video bios part.
The file posted by magicvoodooable should be better suited.

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Reply 3 of 5, by magicvoodooable

Posted on 2022-09-27, 02:45

magicvoodooable Offline

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Yes I have tried several different jumper configurations from various sources.
I have ordered AMD and Cyrix based CPUs to see if that makes a difference.
I’m worried the board has some other hidden damage and hence the “always no POST code” situation.
I will provide further feedback once I have these CPUs.

Reply 4 of 5, by magicvoodooable

Posted on 2022-10-06, 00:05

magicvoodooable Offline

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So I got a Cyrix DX2 66 processor, basically the one the motherboard is expecting (i.e. has the proper jumper config written in the silkscreen)... but still no sign of life 🙁
No P.O.S.T. code whatsoever. Must be something else.

Does anyone else have this motherboard and had issues getting it to even spit out a P.O.S.T. code?

Reply 5 of 5, by rasz_pl

Posted on 2022-10-06, 22:26

rasz_pl Offline

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battery near cpu spells lots of trouble if it leaks, as evidenced by the bodges on retroweb picture

Open Source AT&T Globalyst/NCR/FIC 486-GAC-2 proprietary Cache Module reproduction

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