VOGONS


First post, by appiah4

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The question below is resolved, but the more relevant issue is in the 8th post.

Recently acquired this motherboard and want to set up a 486 system on it.

med_gallery_60983_11505_111867.jpg

A larger photo can be found here.

However, finding a manual or jumper settings about it has been impossible with my google-fu. My searches have led me to to this site which identifies it as an MB457 V1.1 (UM8498F) and through further research I discovered this wimsbios thread whereby edwin appears to have ID'ed the manufacturer as ADI and Rainbow seems to have figured out jumper settings but never got around to make the micromanual for jumper settings. I tried to contact him but he's been inactive for over a decade and no contact links are on his site.

So that leaves me in a rut.. I'm asking here in a futile last hope that someone is familiar with this board or can visually ID what jumper/header does what, as I am fairly limited in my pre-pentium hardware experience and not even sure that the configuration it shipped in will work and not fry something..

Last edited by appiah4 on 2017-06-06, 13:30. Edited 3 times in total.

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 2 of 9, by Skyscraper

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I don't think you need to worry about jumpers on that motherboard.

The three jumpers in the upper right corner are for changing the FSB if I remember correctly and the jumper on the 4 pin battery header keeps the BIOS settings (if the battery works).

The other jumpers near the battery probably enables the other 486 socket and disables the onboard UMC 486 SX CPU but as the other socket isn't even there you can ignore them.

I would not be afraid of testing the motherboard as it is.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 3 of 9, by appiah4

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Thanks; I was hoping the 4 pin below the battery was an External Battery connector but I guess it's not.. Never saw a 4 pin CMOS clear jumper before.

I could try experimenting with the upper right FSB jumpers.. How safe would it be to run this board at 40MHz? I've seen U5SX 486-33 and U5SX 486-33F/40 but this is a U5SX 486-33F so I don't know if it would run?

There are also two pairs of jumpers to the left of the UM8496F chip (J7/J8 shorted) and the third ISA slot (J9/J10 open) any guesses as to what these could be?

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 4 of 9, by kixs

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4-pin jumpers directly bellow the battery is almost for sure external bat. connector. On the side of the battery are jumpers for setting the CPU type. But on your board CPU is soldered so leave it as is. Not sure about the others.

Requests are also possible... /msg kixs

Reply 5 of 9, by Skyscraper

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The battery header is both a battery header for an external battery and where you clear the BIOS settngs.

The jumper closes the circuit and connects the onboard battery to the BIOS chip. If you remove the jumper you dsconnect the onboard battery and clear the BIOS settings. Do not move the jumper to the other two pins!

If you want to use an external battery you remove the jumper and connect the battery to the header. To clear the BIOS settings you simply remove the battery cable from the header.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 6 of 9, by appiah4

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Skyscraper wrote:

The battery header is both a battery header for an external battery and where you clear the BIOS settngs.

The jumper closes the circuit and connects the onboard battery to the BIOS chip. If you remove the jumper you dsconnect the onboard battery and clear the BIOS settings. Do not move the jumper to the other two pins!

If you want to use an external battery you remove the jumper and connect the battery to the header. To clear the BIOS settings you simply remove the battery cable from the header.

Ooh nice, so I can just clip off the barrel battery and connect a 3,6V 3xAAA pack with a 4 2 pin connector instead? do I connect it to the pins that are currently closed? The other 2 pins are ground pins I guess?

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 7 of 9, by Skyscraper

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appiah4 wrote:
Skyscraper wrote:

The battery header is both a battery header for an external battery and where you clear the BIOS settngs.

The jumper closes the circuit and connects the onboard battery to the BIOS chip. If you remove the jumper you dsconnect the onboard battery and clear the BIOS settings. Do not move the jumper to the other two pins!

If you want to use an external battery you remove the jumper and connect the battery to the header. To clear the BIOS settings you simply remove the battery cable from the header.

Ooh nice, so I can just clip off the barrel battery and connect a 3,6V 3xAAA pack with a 4 2 pin connector instead? do I connect it to the pins that are currently closed? The other 2 pins are ground pins I guess?

You normally connect the external battery to pin 1 and 4, one of them is ground and the other + (the ones furthest away from each other). One of the pins is often marked with a "+" sign so you know which way to connect the cable. (Pin 1 should be + I would think but check that pin 4 is connected to ground with a DMM to make sure.)

Your battery header (or how I think your battery header works).

4 3 2 1 (Pin numbers)
- - + + "Pin 2" (+) is connected to the soldered on battery + and "pin 1" (+) is connected to the BIOS chip +, the jumper connects the two.

("Pin 3" could just aswell be "NC" = not connected but this dosn't matter.)

External battery - goes on "pin 4" and + on "pin 1", but as I wrote above double check with a DMM before connecting an external battery.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 8 of 9, by appiah4

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Sorry for resurrecting this old thread but as I am fixing to build this PC, I stumbled onto something strange. Here's the photo of my board:

med_gallery_60983_11505_566374.jpg

And here is a photo of the same board on Amoretro:

med_gallery_60983_11505_1217541.jpg

I was comparing jumper settings to determine how to run it at 40Mhz, which I found - but here is the kicker..

My board has almost no caps? Some other components also seem suspiciously absent:

F1 (shorted)
L1, L2 (Shorted)
C1, C9. C10, C11, C12, C13, C14 (different component), C15, C16, C19, C20, C23, C24
CT1, CT2, CT3, CT4, CT5, CT6 (different component), CT7, CT8 (different component), CT9, CT10 (different component), CT11, CT12 (different component), CT13, CT14, CT15, CT16, CT17

I believe they have all been deliberately removed for some reason? Strangely enough they look like they've never been soldered on rather than removed and some of them are outright wrong..

I'd be correct to assume trying to run this board without the caps would be disastrous? Should I try to find and add the missing/wrong components? Can anyone help me identify the missing compnents to begin with? I can't find any shots of this board that has the cap specs visible 🙁

Here's the original, high res version of the image on Amoretro

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 9 of 9, by TheMobRules

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appiah4 wrote:

I believe they have all been deliberately removed for some reason? Strangely enough they look like they've never been soldered on rather than removed and some of them are outright wrong..

If they look like they've never been soldered then most likely those components were not there in the first place. The other board may be a different revision of the same model, and these differences are usual as it allows the manufacturer to use the same PCB.

I agree with the others, it should be pretty safe to test it as it is, especially considering that the CPU is soldered and there are not many jumpers to change. You should only worry about replacing/adding components if some were broken off or are clearly damaged.