VOGONS


First post, by feipoa

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I have two PC Chips M912 motherboards which I got for free some years ago. One has PCB revision 1.4, the other is revision 1.7. I've seen 3 different jumper settings online which are supposedly for the AMD Am5x86, however none of them work. I power up the board, but there is no display shown on the monitor. This motherboard came with the following AMI BIOS revision,

BIOS Release = 12/02/1994
AMI Date = 7/25/94

Does anyone have a newer BIOS or know which jumper settings are proven to work with the Am5x86-133? The Intel DX4-100 works fine in Write-back mode. The Cyrix 5x86 as least attempts to boot, but stalls in early boot (perhaps related to the VLB SCSI card?).

This motherboard is based on the UMC Um4980 chipset. I realise it is not the most sought after board, but I at least would like to get it running with the Am5x86-160 so that I can compare it with an ASUS board based on the SiS471 chipset.

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Reply 1 of 16, by BastlerMike

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Fully configured for Am5x86:

PCChips M912_2.JPG
Filename
PCChips M912_2.JPG
File size
1.12 MiB
Views
1680 views
File license
Fair use/fair dealing exception

Bios:

Filename
M912.rar
File size
60.32 KiB
Downloads
192 downloads
File license
Fair use/fair dealing exception

Reply 2 of 16, by feipoa

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Much appreciated! How did you find this BIOS version?
I also noticed that you are not using the P24D (Intel DX4 WB) jumper settings which are silk screened onto your motherboard.

Ultimate 486 Benchmark | Ultimate 686 Benchmark | Cyrix 5x86 Enhancements | 486 Overkill Graphics | Worlds Fastest 486

Reply 4 of 16, by feipoa

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I managed to find an m912 BIOS in my archives with date 12/02/1995X. I'm not sure what the X is for or where I found the BIOS, but I used it and it works fine with my AMD X5 at 160 MHz.

I tried using DIP-32 EEPROM's in the PC Chips M912, but they would not work, irregardless of what I set JP2 and JP3 at.

Attachments

  • Filename
    M912_12-02-1995X.zip
    File size
    60.52 KiB
    Downloads
    193 downloads
    File license
    Fair use/fair dealing exception

Ultimate 486 Benchmark | Ultimate 686 Benchmark | Cyrix 5x86 Enhancements | 486 Overkill Graphics | Worlds Fastest 486

Reply 5 of 16, by jsp

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Hi,

sorry for resurrecting this old thread, just wanted to report that I could get my m912 to work with an AMD 5x86 (at both 133 and 160 Mhz) thanks to the information of this post. I am using the bios contributed by feipoa, but probably the one uploaded by BlasterMike works just fine as well.

About reflashing the Bios, the rom in my board was an OTP so I had to desolder the IC from the motherboard and replace it with another eprom flashed with the appropriate bios. This proved to be quite tricky as the eprom was soldered directly to the board instead of being placed in a socket. I also had to buy a programmer (TL866) for flashing the bios into the new eprom. Finally I soldered a socket into the placed left after removing the old eprom to avoid having to repeat the process if I ever need to.

If anybody dares to go this route, my advice is to cut the pins of the soldered rom and extract each pin individually unless you have the proper tools for desoldering such a massive IC. I ended up damaging my board pretty significantly during the procedure, and unfortunately had to bridge 4 connections using wires from the eprom to the pins of the first ISA slot.The good news is that it's working, but I'm pretty sure I'll need to plate back some of the holes in the future as the connections don't look 100% reliable.

Next stage of this trip: replace the damn fake cache ICs. Lot's of desoldering+soldering (9x28 pins), it will have wait until next year 😁

Reply 6 of 16, by feipoa

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Damaging some traces is just part of the learning curve. I'm sure its happened to everyone.

Ultimate 486 Benchmark | Ultimate 686 Benchmark | Cyrix 5x86 Enhancements | 486 Overkill Graphics | Worlds Fastest 486

Reply 8 of 16, by Nexxen

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jsp wrote on 2018-09-01, 18:10:
Hi, […]
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Hi,

sorry for resurrecting this old thread, just wanted to report that I could get my m912 to work with an AMD 5x86 (at both 133 and 160 Mhz) thanks to the information of this post. I am using the bios contributed by feipoa, but probably the one uploaded by BlasterMike works just fine as well.

About reflashing the Bios, the rom in my board was an OTP so I had to desolder the IC from the motherboard and replace it with another eprom flashed with the appropriate bios. This proved to be quite tricky as the eprom was soldered directly to the board instead of being placed in a socket. I also had to buy a programmer (TL866) for flashing the bios into the new eprom. Finally I soldered a socket into the placed left after removing the old eprom to avoid having to repeat the process if I ever need to.

If anybody dares to go this route, my advice is to cut the pins of the soldered rom and extract each pin individually unless you have the proper tools for desoldering such a massive IC. I ended up damaging my board pretty significantly during the procedure, and unfortunately had to bridge 4 connections using wires from the eprom to the pins of the first ISA slot.The good news is that it's working, but I'm pretty sure I'll need to plate back some of the holes in the future as the connections don't look 100% reliable.

Next stage of this trip: replace the damn fake cache ICs. Lot's of desoldering+soldering (9x28 pins), it will have wait until next year 😁

Have you tried replacing the fake chips? I would like to try that and see if it works, but a word of advice is welcome if someone has done it before. 😀

Reply 9 of 16, by jsp

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Hi,
sorry for the late response to this question, it's been a while since I logged in the forum. Unfortunately, I haven't had time to replace the fake cache chips on the board. It is pretty substantial amount of work, and I just don't have the time at the present time. If anybody has success with this please let us know!

Thanks

Nexxen wrote on 2020-03-19, 18:24:
jsp wrote on 2018-09-01, 18:10:
Hi, […]
Show full quote

Hi,

sorry for resurrecting this old thread, just wanted to report that I could get my m912 to work with an AMD 5x86 (at both 133 and 160 Mhz) thanks to the information of this post. I am using the bios contributed by feipoa, but probably the one uploaded by BlasterMike works just fine as well.

About reflashing the Bios, the rom in my board was an OTP so I had to desolder the IC from the motherboard and replace it with another eprom flashed with the appropriate bios. This proved to be quite tricky as the eprom was soldered directly to the board instead of being placed in a socket. I also had to buy a programmer (TL866) for flashing the bios into the new eprom. Finally I soldered a socket into the placed left after removing the old eprom to avoid having to repeat the process if I ever need to.

If anybody dares to go this route, my advice is to cut the pins of the soldered rom and extract each pin individually unless you have the proper tools for desoldering such a massive IC. I ended up damaging my board pretty significantly during the procedure, and unfortunately had to bridge 4 connections using wires from the eprom to the pins of the first ISA slot.The good news is that it's working, but I'm pretty sure I'll need to plate back some of the holes in the future as the connections don't look 100% reliable.

Next stage of this trip: replace the damn fake cache ICs. Lot's of desoldering+soldering (9x28 pins), it will have wait until next year 😁

Have you tried replacing the fake chips? I would like to try that and see if it works, but a word of advice is welcome if someone has done it before. 😀

Reply 10 of 16, by Nexxen

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I am on the way and I "just" need to figure out the smd capacitors value that goes with the cache chips, as they aren't on the board.

Desoldering and resoldering is the real issue here... 🤣
I'll report back my results. I still have to benchmark the board before the changes to see how much it affected performance, but I guess that the 486 figures aren't going to change much as in the super benchmark in Marvin forum.
After 20+ years I want answers 😀

Reply 11 of 16, by ricardo.contieri

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Hi all!

As this topic is "kinda" alive, I'd ask if anyone was able to get this version of the bios that was published back in the day on PCChips website.

M912 Mainboard:

9121201.bin checksum: * 2DC3 *
BIOS Date:12/01/1995
Board Description:UMC8498, UMC8496 Chips
BIOS Features:To support Cyrix5x86, AMD DX4

Source: http://web.archive.org/web/19980214052149fw_/ … _mainboard_bios

If anyone has captured that version, it would be great to share!

Thanks in advance!

Reply 12 of 16, by darry

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ricardo.contieri wrote on 2020-09-16, 03:16:
Hi all! […]
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Hi all!

As this topic is "kinda" alive, I'd ask if anyone was able to get this version of the bios that was published back in the day on PCChips website.

M912 Mainboard:

9121201.bin checksum: * 2DC3 *
BIOS Date:12/01/1995
Board Description:UMC8498, UMC8496 Chips
BIOS Features:To support Cyrix5x86, AMD DX4

Source: http://web.archive.org/web/19980214052149fw_/ … _mainboard_bios

If anyone has captured that version, it would be great to share!

Thanks in advance!

I found the filenames on the Internet . Not what you are looking for, but maybe of interest .
Hard to say what is actually newer .

9190914s.rom is in 980914s.zip

Filename
980914s.zip
File size
84.25 KiB
Downloads
2 downloads
File license
Fair use/fair dealing exception

9191016s.bin is in 961016s.zip

Filename
961016s.zip
File size
114.89 KiB
Downloads
2 downloads
File license
Fair use/fair dealing exception

https://web.archive.org/web/20010112030700/ht … port/mb_912.htm

EDIT: I can't even be sure these are actually for the M912 or not .

EDIT2: Found it here : https://www.elhvb.com/mboards/pcchips/486_M9x … M912/index.html But the file is unfortunately corrupted .[/s]

EDIT 3: Found it here and it seems OK .
https://www.elhvb.com/mobokive/archive/pcchip … 9951201_AMI.zip

Filename
912_Bios_19951201_AMI.zip
File size
60.5 KiB
Downloads
3 downloads
File license
Public domain

Reply 13 of 16, by darry

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darry wrote on 2020-09-16, 03:52:
I found the filenames on the Internet . Not what you are looking for, but maybe of interest . Hard to say what is actually newe […]
Show full quote
ricardo.contieri wrote on 2020-09-16, 03:16:
Hi all! […]
Show full quote

Hi all!

As this topic is "kinda" alive, I'd ask if anyone was able to get this version of the bios that was published back in the day on PCChips website.

M912 Mainboard:

9121201.bin checksum: * 2DC3 *
BIOS Date:12/01/1995
Board Description:UMC8498, UMC8496 Chips
BIOS Features:To support Cyrix5x86, AMD DX4

Source: http://web.archive.org/web/19980214052149fw_/ … _mainboard_bios

If anyone has captured that version, it would be great to share!

Thanks in advance!

I found the filenames on the Internet . Not what you are looking for, but maybe of interest .
Hard to say what is actually newer .

9190914s.rom is in 980914s.zip 980914s.zip
9191016s.bin is in 961016s.zip 961016s.zip

https://web.archive.org/web/20010112030700/ht … port/mb_912.htm

EDIT: I can't even be sure these are actually for the M912 or not .

EDIT2: Found it here : https://www.elhvb.com/mboards/pcchips/486_M9x … M912/index.html But the file is unfortunately corrupted .

EDIT 3: Found it here and it seems OK .
https://www.elhvb.com/mobokive/archive/pcchip … 9951201_AMI.zip
912_Bios_19951201_AMI.zip

Replied to myself in order to bump because the file requested was found .

Reply 14 of 16, by jakethompson1

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ricardo.contieri wrote on 2020-09-16, 03:16:
Hi all! […]
Show full quote

Hi all!

As this topic is "kinda" alive, I'd ask if anyone was able to get this version of the bios that was published back in the day on PCChips website.

M912 Mainboard:

9121201.bin checksum: * 2DC3 *
BIOS Date:12/01/1995
Board Description:UMC8498, UMC8496 Chips
BIOS Features:To support Cyrix5x86, AMD DX4

Source: http://web.archive.org/web/19980214052149fw_/ … _mainboard_bios

If anyone has captured that version, it would be great to share!

Thanks in advance!

I don't know how to check the checksum, but my board came with a 12/01/95 BIOS.
I wonder if you could compare cachechk numbers especially how cachechk -w compares to cachechk:

https://www.vogons.org/viewtopic.php?f=46&t=76564

Attachments

  • Filename
    120195.zip
    File size
    60.55 KiB
    Downloads
    2 downloads
    File license
    Public domain

Reply 15 of 16, by jakethompson1

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jakethompson1 wrote on 2020-09-18, 00:08:
ricardo.contieri wrote on 2020-09-16, 03:16:
Hi all! […]
Show full quote

Hi all!

As this topic is "kinda" alive, I'd ask if anyone was able to get this version of the bios that was published back in the day on PCChips website.

M912 Mainboard:

9121201.bin checksum: * 2DC3 *
BIOS Date:12/01/1995
Board Description:UMC8498, UMC8496 Chips
BIOS Features:To support Cyrix5x86, AMD DX4

Source: http://web.archive.org/web/19980214052149fw_/ … _mainboard_bios

If anyone has captured that version, it would be great to share!

Thanks in advance!

I don't know how to check the checksum, but my board came with a 12/01/95 BIOS.
I wonder if you could compare cachechk numbers especially how cachechk -w compares to cachechk: M912 v1.7 - both caches always perform as write through

Reply 16 of 16, by ricardo.contieri

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For the checksum of files (and all the other hash calculation) I like the hashcalc tool (if you want to check the integrity of the BIOS). It's a very light program, that can run starting with Win 95.

https://www.slavasoft.com/hashcalc/

But no idea for how to checksum of what is in the cache, though...

And thanks to all who has sent those files! I guess they are not on the file section of Vogons... Now I just need one EPROM that can fit those bios and try them out!

Best,

Ricardo