VOGONS


First post, by jesolo

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Maybe I should start out by saying why I'm posting this and then asking the relevant questions.

The first PC that I bought for myself had a "hybrid" 3/486 motherboard that could accept both 386 & 5v 486 CPU's (there has been numerous posts about these type of motherboards and that, for example, some of these motherboards' VLB slots only worked with 486 CPU's).
My motherboard utilises the Opti 495XLC chipset with a 386DX AMIBIOS onboard.

A couple of years ago (after removing it from storage), it didn't want to boot up anymore.
A while later, I came into posession of two 386DX AMIBIOS chips and swopped the BIOS chip out.
Sure enough, the motherboard booted up, but wouldn't boot post the main memory count down screen.
I realised that the BIOS chip was from a motherboard that utilised an ALI chipset and not an OPTI chipset (which made sense), but at least I knew what the source of the problem was.

At this point, I'm trying to obtain a replacement 386DX AMIBIOS for my OPTI 495XLC motherboard, but I've seen similar hybrid motherboards that utilises the Opti 495SLC and Opti 495SX chipsets.
Finding some of these Opti based motherboards (preferably a "defective" one, so that I don't have to pay a fortune for it), is also proving to be challenging.
What is also strange is that some of these motherboards has a 486DX AMIBIOS and not a 386DX AMIBIOS.
I've read that BIOS chips from motherboards with similar chipsets should work with each other.

Coming to my questions:

What are the differences between the Opti 495SX, SLC & XLC chipsets?
Will a BIOS from a motherboard with one Opti 495 chipset work with a motherboard that has another Opti 495 chipset (for example, will a BIOS from an Opti 495SLC chipset based motherboard work with a motherboard that has an Opti 495XLC chipset)?
Does it matter whether the BIOS states 386DX AMIBIOS or 486DX AMIBIOS, if they are from an Opti 495 based chipset?

Reply 1 of 11, by kixs

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I have two 386/486 Opti boards and they both have MR.BIOS.

495SX:
http://i.imgur.com/jdmN28r.jpg

495SLC:
http://i.imgur.com/1JcqN6E.jpg

Can't say about their differences as I never looked into it.

Requests are also possible... /msg kixs

Reply 2 of 11, by nforce4max

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I already had to do this on one board and there was no way I was going to find a rom online let alone the documentation (already tried). The bios was gone so I found another board with the same chipset that was beyond repair and took the bios from that, the bios swap worked so you are on the right track. The board I did this on was a 5v 486 board that is running a 50mhz dx.

Find another board that uses the same chipset and swap it over, if you got an eprom burner you can pull the rom and burn a new one for this board. I got the 495 slc hybrid board that has the mr bios but haven't done anything with it yet.

Edit: http://www.ebay.com/itm/EDOM-MA013-386DX-Mini … DAAAOSw14xXEeYW

Maybe contact the seller and see if he or she is willing to cut you a deal?

On a far away planet reading your posts in the year 10,191.

Reply 3 of 11, by kixs

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I should have a 386 only board with 495XLC chipset and AMI BIOS but I doubt it will work on a 3/486 hybrid board. I'll check later.

Requests are also possible... /msg kixs

Reply 4 of 11, by Joyride

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kixs wrote on 2016-07-03, 16:08:
I have two 386/486 Opti boards and they both have MR.BIOS. […]
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I have two 386/486 Opti boards and they both have MR.BIOS.

495SX:
http://i.imgur.com/jdmN28r.jpg

495SLC:
http://i.imgur.com/1JcqN6E.jpg

Can't say about their differences as I never looked into it.

Hi! Can you please help me?
I need that MR-BIOS that you have on your 495SLC board. I have the same with faulty bios.
Is it possible that you can copy it?
Best regards /Rickard

Reply 5 of 11, by kixs

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Joyride wrote on 2020-11-13, 23:23:
Hi! Can you please help me? I need that MR-BIOS that you have on your 495SLC board. I have the same with faulty bios. Is it poss […]
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kixs wrote on 2016-07-03, 16:08:
I have two 386/486 Opti boards and they both have MR.BIOS. […]
Show full quote

I have two 386/486 Opti boards and they both have MR.BIOS.

495SX:
http://i.imgur.com/jdmN28r.jpg

495SLC:
http://i.imgur.com/1JcqN6E.jpg

Can't say about their differences as I never looked into it.

Hi! Can you please help me?
I need that MR-BIOS that you have on your 495SLC board. I have the same with faulty bios.
Is it possible that you can copy it?
Best regards /Rickard

I guess I missed this... do you still need it?

Requests are also possible... /msg kixs

Reply 6 of 11, by ltning

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kixs wrote on 2022-01-25, 13:29:
Joyride wrote on 2020-11-13, 23:23:
Hi! Can you please help me? I need that MR-BIOS that you have on your 495SLC board. I have the same with faulty bios. Is it poss […]
Show full quote
kixs wrote on 2016-07-03, 16:08:
I have two 386/486 Opti boards and they both have MR.BIOS. […]
Show full quote

I have two 386/486 Opti boards and they both have MR.BIOS.

495SX:
http://i.imgur.com/jdmN28r.jpg

495SLC:
http://i.imgur.com/1JcqN6E.jpg

Can't say about their differences as I never looked into it.

Hi! Can you please help me?
I need that MR-BIOS that you have on your 495SLC board. I have the same with faulty bios.
Is it possible that you can copy it?
Best regards /Rickard

I guess I missed this... do you still need it?

I guess I do .. just got my 495SLC going and been looking for MR-BIOS for it.. :)

The Floppy Museum - on a floppy, on a 286: http://floppy.museum
286-24/4MB/ET4kW32/GUS+SBPro2
386DX-40/20MB/CL5434 ISA/GUSExtreme
486BL-100/32MB/ET4kW32p VLB/GUSPnP/AWELegacy

~ love over gold ~

Reply 8 of 11, by ltning

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kixs wrote on 2022-02-03, 03:14:

I will need to find the board now...

Would be awesome. Though, the board works extremely well already - downgraded to a DX33 (while trying to get hold an Am386dx40) and using a very decent VLB graphics card and a Tekram VLB cache controller .. only real problem is that counting 64MB RAM takes forever with the original BIOS..

The Floppy Museum - on a floppy, on a 286: http://floppy.museum
286-24/4MB/ET4kW32/GUS+SBPro2
386DX-40/20MB/CL5434 ISA/GUSExtreme
486BL-100/32MB/ET4kW32p VLB/GUSPnP/AWELegacy

~ love over gold ~

Reply 10 of 11, by kixs

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romdump wrote on 2022-08-11, 23:31:
kixs wrote on 2022-02-03, 03:14:

I will need to find the board now...

Did you ever find the board and dumped the BIOS?

Looking at the photo of the 495slc board... it looks like it has an AMI BIOS. MR.BIOS is for the keyboard or something...

Requests are also possible... /msg kixs

Reply 11 of 11, by romdump

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kixs wrote on 2022-08-13, 23:18:

Looking at the photo of the 495slc board... it looks like it has an AMI BIOS. MR.BIOS is for the keyboard or something...

The MR BIOS in the picture is the Keyboard controller.

I think we are still looking for the MR BIOS for the 495SLC. I had downloaded it from OPTI ftp server in the late 90's but now I realize the file is corrupted during the download.