Even if bits could be found in the BIOS, it would be extremely risky to flash it, because of the flash memory chip. It probably uses a checksum as well, which would make patching even harder.

Babasha wrote on 2022-10-28, 11:27:

There are Mr.BIOS'es for this motherboard (with their pros and cons)

Does it support the integrated S3 ViRGE? The video ROM is probably part of the BIOS.

The orientation of the ATX power connector is brain damaged.

There are different versions of Mr.BIOS for MB with or without onboard video (or with S3 Virge or S3 Virge/DX). Be careful there is Mr.BIOS for ARCADE variant of motherboard (no way to downgrade - only with recovery jumper and boot floppy disk with AMI BIOS) 😀

Kahenraz wrote on 2022-10-28, 11:28:

Babasha wrote on 2022-10-28, 11:27:

There are Mr.BIOS'es for this motherboard (with their pros and cons)

Does it support the integrated S3 ViRGE? The video ROM is probably part of the BIOS.

Might be worth investigating to see if Intel released an updated BIOS with S3 fixes, for me personally the S3 gamma bug would have me shelving this board or adding a S3 PCI card that doesn't have this bug.

Kahenraz wrote:

I've seen this board crop up a few times, but never with both the integrated video and General MIDI option. It must have been very expensive at the time

Most likely the opposite is true. That is one of the most common and mass produced standard OEM 430HX boards, which was adopted by many brands. Minimal amount of caps and simplified VRM, thanks to ATX standard with added +3.3v rail. Modular design and cheapest optional features like S3 and Yamaha chips, also specifically targeted for OEM market for lowest price.

By rare and expensive, I meant the the model that provided both integrated video and sound with General MIDI. I see this board more often without one or the other, or either.

I noticed markings for an slot below the onboard cache. Was the purpose of this slot to cost-reduce the board by selling it without any onboard cache? I'm guessing that it isn't meant to be there if there is already cache soldered to the board. I couldn't find any photos of this board with that slot present, to confirm any particular configuration. Maybe it was meant to be an OEM option and was never used there either.

Kahenraz wrote on 2022-10-28, 08:27:

Intel motherboards from this time use a really annoying surface mount flash chip that I can't remove to flash elsewhere. The board would have to be capable of blindly flashing from a floppy disk.

20221028_042601.jpg

Do I see dip32 pads under that chip?

Reading farther: sweet! Got it working!

What processor will you use in the build? I gather this will be a dos box of modest specs?

Kahenraz wrote on 2022-10-28, 12:12:

By rare and expensive, I meant the the model that provided both integrated video and sound with General MIDI. I see this board more often without one or the other, or either.

I noticed markings for an slot below the onboard cache. Was the purpose of this slot to cost-reduce the board by selling it without any onboard cache? I'm guessing that it isn't meant to be there if there is already cache soldered to the board. I couldn't find any photos of this board with that slot present, to confirm any particular configuration. Maybe it was meant to be an OEM option and was never used there either.

Coast Module slot, doubt Intel ever used it but OEMs might for various cache options.

TrashPanda wrote on 2022-10-28, 16:23:

Kahenraz wrote on 2022-10-28, 12:12:

By rare and expensive, I meant the the model that provided both integrated video and sound with General MIDI. I see this board more often without one or the other, or either.

I noticed markings for an slot below the onboard cache. Was the purpose of this slot to cost-reduce the board by selling it without any onboard cache? I'm guessing that it isn't meant to be there if there is already cache soldered to the board. I couldn't find any photos of this board with that slot present, to confirm any particular configuration. Maybe it was meant to be an OEM option and was never used there either.

Coast Module slot, doubt Intel ever used it but OEMs might for various cache options.

Yeah, it's marked CELP, which is apparently a card edge low profile slot. I'd guess that if you're Dell (or whoever) it works out easier to have a bunch of identical motherboards and then plug in either 512kB or 256kB sticks when putting all the bits together. I know the Dell Dimension PxxxS used a COASt stick. But if Intel put together a reference design to show off various options then they'd want to include as many options as they can in the board layout.

Kahenraz wrote on 2022-10-28, 11:28:

Even if bits could be found in the BIOS, it would be extremely risky to flash it, because of the flash memory chip. It probably uses a checksum as well, which would make patching even harder.

The utility SVBL (Shadow Video BIOS loader) might help to load the bug-free vbios

At some point, when SRAM cache chips became cheaper, many manufacturers spared the CELP slot, since with 2 x 256K (64Kx8) the boards were maxed out L2 cache-wise - just as your board here.
The mistake often made was to remove the CELP slot and leave the mainboard design unchanged to only take one TAG chip so the cacheable area stayed nailed to 64MB despite having 512K L2 cache available.
With a CELP slot still popuated and only 256K onboard cache the user could have upgraded with a 256K COAST stick equipped with a 2nd TAG chip. Only then the full cacheable area of 512MB - that the HX chiposet is appreciated for - can be used.

How much memory is supported in this configuration? This will be my first board with this memory type. What is it, EDO? The BIOS shows that there is 512KB of cache.

Sphere478 wrote on 2022-10-28, 15:52:

Do I see dip32 pads under that chip?

It might be. But it's configured for Flash memory. I don't know if it needs modification to work with a CMOS chip, or even what kind of chip it would need. It would be too risky to experiment with my only board.

Sphere478 wrote on 2022-10-28, 15:52:

What processor will you use in the build? I gather this will be a dos box of modest specs?

I have no idea. I scooped it up primarily because of the Yamaha+GM with onboard S3 combo. I can't see myself ever using it unless I can resolve the brightness problem though. Might be possible with the video shadow ROM, if I can find a compatible one.

Of all irony, all the intel-made HX based boards, no second tag ram solder pads, forcing you to figure out to install CELP slot and add missing components.

But does there is specific conditions that you need a COAST module that has second tag wired correctly on these modules to enable 512K with dual tag working on these boards?

Cheers,

Calamitylime made a nice thread about this

What would be the benefit of this slot? Can it function in addition to the onboard memory?

There is also another issue with the S3 video chip. When the CPU bus is clocked at 50 Mhz, my LCD will sometimes be unavailable to sync with it. This occurs after the BIOS screen when the system starts to boot the OS, and can be mitigated by entering the BIOS and then proceeding to boot after exiting it.

and to add some fuel to the fire, theres two ways the CELP slot could be wired.
1 with the traces for the second tag ram
2 without the traces for the second tag ram.

So you can't always just wire to the TIO lines on the CELP instead you can solder to the chipset and that'll work! after some bios mods.

That sounds terrifying. Soldering onto the chipset, and modifying the BIOS on this board. I'm afraid to touch this BIOS, since it isn't a chip I can put into my programmer.

oh yea, yeah it was.
Worked though.

It's also a great way to introduce weird ram errors if you're using sockets that are not spotless.

I managed to fix the overbright issue by flashing another BIOS using shadow ROM with svbl.

Luckily, this tool specifically supports the Triton chipset (Intel 430HX). Here is the command I used:

svbl.com /c:triton.cps /b:86C375_5.bin

Neither s3bright.com nor s3black.com worked with this onboard card. I know that these utilities work with other cards, since I have tried them in the past with my S3 Trio 3D/2X.

I've attached everything needed to get this working, in case anyone else finds themselves with this same problem in the future.

Here is a link to the other relevant thread:

S3 AGP Cards (and possibly others) Too Bright

This is where to obtain s3bright (which doesn't work with this card):

Re: S3 AGP Cards (and possibly others) Too Bright

And s3vbefix (which also doesn't work with this card):

S3VBEFIX - PC\MS-DOS TSR fix for S3 VESA 2.0 video BIOS

I also tried using DEBUG to modify the BLANK pedestal, as described by wbc, which also does not work with this card:

Re: S3 AGP Cards (and possibly others) Too Bright

1o 3c4 08
2o 3c5 06
3o 3c4 27
4i 3c5
5<at this step subtract 08h from given value>
6o 3c5 <resulting_value>
7q

I found a working BIOS here, and tied 86C375_1.bin, 86C375_2.bin, 86C375_3.bin, 86C375_4.bin, and 86C375_5.bin. 1, 3, and 4 all had the overbright problem. There was some error with 2 that made it fail to load. The only one to produced the correct black levels was 86C375_5.bin.

http://chukaev.ru54.com/video_en.htm

Good job looking out for the next person. Gotta document everything!

Good job uploading it also!