VOGONS


First post, by keropi

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Hiya!

I recently got a Soyo 4SA2 motherboard and I was wondering what the latest BIOS is for this mobo - and if anyone made a LBA48 HDD patch?
I found some BIOS files on retronn.de -> ftp.retronn.de/mirrors/www.elhvb.com_mobokive/Soyo/bios/486/
4sa-iob1.bin seems to be the latest official one from 1995
4sa0730.bin seems to be a 1997 one but no idea what was added/patched

If anyone knows more about it please reply , the board seems very nice.

ps.
I added the missing components so now the board has a working ps/2 mouseport - I just followed madowax's instructions 🤣
inductors and 47pf caps stolen from a dead ss7 mobo, added the extra 4.7k pullup resistors for the mouse data and clock lines and connected keyboard controller pin36 to the IRQ12 pin on an isa slot. The stock BIOS did not have mouse functions enabled so I used modbin but the later ones above have it enabled by default.
Everything with a pink dot was added to make the ps/2 header working, maybe it helps someone else to add the components:

JerQJlZl.jpg

I am now also wondering if removing D2 will prevent the battery from charging like it was with the 4SAW2 mobo - so I can just solder a CR2032 and call it a day....

🎵 🎧 PCMIDI MPU , Orpheus , Action Rewind , Megacard and MK8330 soundcard website

Reply 1 of 11, by SteliosG

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Hello Keropi and fellow Vogoners ! 😀

First post here !

I recently managed to find the same board and I also did the ps/2 mod , but without the pull up resistors . Can you please show me a picture of the place you added the resistors ? Are they there for safety ? I read something about current limiting . ???

Regarding the bios , I downloaded the pack from the vogons drivers site : http://www.vogonsdrivers.com/getfile.php?fileid=731

Inside the rar file there is a modded beta bios : 4SAW0911.BIN
I can understand the this bios is for the 4SAW , but as I have a programmer I decided to try it . This bios has support for PS/2 and also for LBA . I tried many HDDs up to 80GB and they are working as expected . I think the limit is 128GB

I'll also check the one from mobokive . I'm curious if it's faster/newer .

Now , about the battery . Yes , I also removed the old battery and replaced with a lithium one . You should remove the middle diode (D2) . I checked it with the multimeter and after removing it the 5v voltage is gone.

EDIT : Tried the bios from mobokive , but it doesn't support large HDDs . So , i am going back to the 4SAW0911.BIN
If someone could patch the other bios it could be awesome , as it has a few more options like tag bits ...

Reply 2 of 11, by keropi

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thanks for the info on the battery situation, I will remove D2 as well 😀
I also tested the two newer 4SA2 BIOSes and can confirm large HDDs do not work with them.
Also noticed that both iob1 and 0730 consume more cpu usage when the ps/2 mouse is moving - seems something changed in IRQ handling? perhaps to help with win95 compatibility.
I tested for example PCPBENCH , normal 320x200 resolution:

BIOS IOA - originally came with my board
PCPBENCH VGA: 12.1
PCPBENCH VGA while constantly moving mouse: 11.8

BIOS IOB1 / 0730
PCPBENCH VGA: 12.8
PCPBENCH VGA while constantly moving mouse: 10.9

I am not sure I want to use the 4SAW bios on the mobo, have you used it long enough ? is it stable?

About the pullups, they are needed because the kb controller pins are open collectors. There are already 4.7K pullups for the keyboard so it makes sense to add them for the mouse as well.
Have a look at this zoomed picture , I used 0805 resistors that's why they are hard to see on the previous pic. R1 is a keyboard pullup so I used it's 5v side for the mouse pullups via a small cable:

Ae863S4l.jpg

full size: https://i.imgur.com/Ae863S4.jpg

Hope this helps!

🎵 🎧 PCMIDI MPU , Orpheus , Action Rewind , Megacard and MK8330 soundcard website

Reply 3 of 11, by SteliosG

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Thanks for the picture ! I just added the resistors . 😀

I got the board not many days ago and all I have done is to install Win98SE . I haven't done any test (benchmarks/stability/gaming).

Regarding the bios , for me it's more crucial to be able to use large HDDs . I'll do some search regarding the procedure of adding LBA support . 😀

Reply 4 of 11, by shock__

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Any recommended values for the inductors? Just got myself a 4sa2 and it turns out to be a great board to be used with a POD100 (contrary to the PVI-486SP3 by Asus it runs absolutely stable and performs pretty much the same).

Current Project: new GUS PnP compatible soundcard

[Z?]

Reply 5 of 11, by kimschi

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shock__ wrote on 2021-05-02, 14:04:

Any recommended values for the inductors? Just got myself a 4sa2 and it turns out to be a great board to be used with a POD100 (contrary to the PVI-486SP3 by Asus it runs absolutely stable and performs pretty much the same).

Hello,

ich have the same mainboard and was wondering, if someone could tell me the values ot the capacitators inductors sitting on L3 and L4 (to buy them), on my board both are missing. I get the "Keyboard error or keyboard not present" error message.
Maybe i'm totally wrong these are not needed an i have look into a different direction.
The board is booting up in general until this keyboard error message.

I would appreciate any answer.

The board is working again, the value is 10uH.

@keropi please could you linkt the tutorial for the ps/2 mod you are reffing ( I just followed madowax's instructions ), i'm planning to do the same.

Reply 7 of 11, by Chkcpu

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mt777 wrote on 2022-06-21, 13:14:

does anyone recognized jumpers for am5x86? such beautiful mobo with 4x pci and 1mb cache and poor doc...

Looking at the user manual at https://www.ultimateretro.net/nl/motherboards/4718, I would use the AMD Enhanced 486DX4-100 jumper settings at page 15 and change jumper JP34 from 1-2 to 2-3. This should run the Am5x86-P75 at 133MHz (4x33) and L1 cache Write-Back mode.

Jan

CPU Identification utility
The Unofficial K6-2+ / K6-III+ page

Reply 9 of 11, by mkarcher

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Chadti99 wrote on 2022-09-24, 22:27:

Anyone had any luck running this board at 160 or 180MHz with an AM5x86?

For me, it works fine at 160MHz (4*40MHz). You need to add a third frequency jumper to be able to select FSB60, but experience at 180MHz (3*60MHz) was poor. It booted once with L2 set to write-through, I could get a cache/memory benchmark using ctcm (the c't cache measurement tool, not the Creative Configuration Manager, of course), but never was able to POST again at 180. I don't know whether it's the board or the chip, though. I went up to 3.6V, I think I even tried once at 4.0V, that didn't change anything. This makes it likely that the board doesn't really work stable at FSB60.

I did obtain DX4-120 in the meantime. If (but that's a big if) I get around to finally fix the 4SA2 for good (it has recurring issues caused by battery leakage), I will try 2*60 in that board, as I know that this processor works fine at 2*60. I tested that in a different board.

Reply 10 of 11, by Chadti99

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mkarcher wrote on 2022-09-25, 07:34:
Chadti99 wrote on 2022-09-24, 22:27:

Anyone had any luck running this board at 160 or 180MHz with an AM5x86?

For me, it works fine at 160MHz (4*40MHz). You need to add a third frequency jumper to be able to select FSB60, but experience at 180MHz (3*60MHz) was poor. It booted once with L2 set to write-through, I could get a cache/memory benchmark using ctcm (the c't cache measurement tool, not the Creative Configuration Manager, of course), but never was able to POST again at 180. I don't know whether it's the board or the chip, though. I went up to 3.6V, I think I even tried once at 4.0V, that didn't change anything. This makes it likely that the board doesn't really work stable at FSB60.

I did obtain DX4-120 in the meantime. If (but that's a big if) I get around to finally fix the 4SA2 for good (it has recurring issues caused by battery leakage), I will try 2*60 in that board, as I know that this processor works fine at 2*60. I tested that in a different board.

Great info, where is this missing 3rd jumper on the board? Looking at the manual you’d think J7 which is in line with JP21 and JP22 would be it.

Any issues with VLB Video?

Reply 11 of 11, by mkarcher

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Chadti99 wrote on 2022-09-25, 09:16:

Great info, where is this missing 3rd jumper on the board? Looking at the manual you’d think J7 which is in line with JP21 and JP22 would be it.

Only two "clock select" pins of the synthesizer chip are routed to jumpers. I added a third one next to JP21 and JP22, on the other side. I soldered it down to GND (available at that place) and ran a bodge wire to the third clock select pin. It's not just fitting a jumper into a position already present on the board. As I didn't glue down the jumper, the solder joint for GND broke and the jumper isn't "installed" anymore. As the 60MHz experience didn't work satisfactory, I didn't bother implementing a more permanent solution yet.

Chadti99 wrote on 2022-09-25, 09:16:

Any issues with VLB Video?

I'm quite sure I used an ISA graphics card for the 60MHz experiment, because FSB60 is finicky enough even without VL cards installed. But you should be aware that the most recent BIOS editions of the 4SA2 initialize the chipset in a wrong way, essentially disabling VL support. Many VL video cards still happen to work, but at an awful performance. The Sis496/7 chipset has a configuration bit that toggles a pair of pins between "request/grant" for a master-capable PCI slot or "LDEV/LRDY" for a VL slot. The latest BIOSes (like the one with 128GB support) set it to PCI req/gnt errorneously.