The corrosion damage does not look bad enough to be the culprit.

Are you sure some of your memory modules are FPM?

This link mentions that this board wont work with EDO.

http://www.os2museum.com/wp/soyo-sy-4saw2-notes/

hi

yes, in the meantime i identified two of the modules as fpm. same behaviour with them...

anyone else got an idea?

edit: audio file with POST beep code attached... (rename from txt to m4a)

Looked at the manual, only thing that stood out was bank 3 simm can only be single sided.
Other than that set everything to defaults then adjust as necessary, but I expect You have already
been there done that.

yep already did that. i guess the motherboard is dead...

Which PCI graphics cards are you trying? Many of these older 486 boards will not work with graphics cards more than a few years newer. Try something simple like S3 Trio. Alternately, for more modern graphics cards, a Voodoo3 or TNT graphics card should work. The chipset on this motherboard does not require memory installation in pairs. Try single sticks of FPM only. I do not beleive the SiS 496/497 chipset will work with EDO. You could also try to flash the BIOS in an external programmer or hot flash it in another motherboard.

If you have an external programmer you might wanna check if the BIOS ROM chip is still good.

I tried an old S3 Trio64 - I also tried only to use one FPM stick.

I don't have an external programmer, how do I hot-flash it? Is there some kind of guide somewhere what to be aware of, ...?
thank you!

Before looking into hot flashing the BIOS, which you need to do this in another motherboard, you should check that the cache jumpers are set correctly, and if so, try swapping the cache modules.

feipoa wrote:

Before looking into hot flashing the BIOS, which you need to do this in another motherboard, you should check that the cache jumpers are set correctly, and if so, try swapping the cache modules.

already did that.. 😀

You could try removing the cache entirely. A google search for "hot flash BIOS" comes up with a lot of step-by-steps guides.

All of which graphics cards have you tried?

On some motherboards, if the diskette or hard drive cable is plugged in incorrectly, the display won't come up. Remove the cable if you haven't done so already. Look for blue or white corrosion on the SIMMs. I've seen this cause similar problems before. Also remove the BIOS chip and check for corrosion.

How many different types/brands of FPM memory modules have you tried? What other motherboards have you tried them in to ensure functionality? I've seen some types cause problems on SiS 496 boards. Also, test only 4 - 32 MB sticks. Many BIOSes for SiS496 boards do not support 64 MB sticks.

i think i already tried to remove the cache entirely - didn't change anything.
I have tried the S3 Trio64 PCI, an old OAK OTI077 ISA card and two CL GD5426 VLB cards.
HDD and FDD weren't connected (lose setup on the table for testing purposes). no corrosion on the SIMMs or the BIOS chip.

I have tried two pairs of different FPM modules, all of them 8MB (also tried to use only one module at a time).

BTW i have another Soyo board here (even older, 25K02) which definitely does not support EDO memory but is working with EDO anyway (2x16MB). Somewhere I read that EDO sticks should behave like FPM sticks if the board doesn't support EDO - just a side note, because I tried EDO and FPM modules on the board. All modules I have tried are working in my older Soyo 25K02 board.

Thanks for your effort! I will google for BIOS hot flash when I find a little time.

Hi nemail,

That problem about the graphic cards is normal with the old PCI motherboards when you try to use newer graphic card than the motherboard. You can find a compatibility list for this motherboard on: Modern graphics on a 486
¿Could you fix the problem with the Soyo 4SAW2 motherboard?. I recently a 4SAW2 without BIOS, the jumper JP2 is welded on the 1-2 position from the manufacture so that this motherboard only accepts FLASH BIOS. This motherboard should be the last revision in the middle of 1996. Do you know the right EEPROM 1Mb for this motherboard?. If somebody has got this motherboard it'll be easy to see the FLASH BIOS used. Thank you.