First make sure the revision of the southbridge (SB82371SB) supports USB. It´s the characters above the "INTEL Ⓜ ©" line, right of the large "i" logo.

Then you need to do sme measuring:
1. Which of the pins of the USB headers are "ground"?
2. Which of the pins of the USB headers are "+5V"?
3. Are the pins 142, 143,144 and 145 connested to pins of the USB headers and to which ones?

https://theretroweb.com/motherboards/s/gigabyte-ga-586dx

In the two higher resolution pictures you can see the bare traces.
I don't know if you have headers on yours or if you soldered them.

You can get a Ground reading easily but, if I'm not mistaken, there is a L1 close to the headers connecting to probably +5V? Check if there you have a +5V where a component isn't soldered.
See picture.

Also, order of the two USB ports look inverted:

A B
+5V Gnd
Data + Data -
Data- Data+
Gnd +5V

SBV0 and 1 are +5V in your picture. The others Data + and -.

I could be totally wrong, check thoroughly.

yes the pinout on the board look odd compared to most (where +5 for both is on one end and ground the other end), this is where one of those Startech or Shuttle USB backpanels with two separate 4/5pin connectors would come in handy.
I would do as suggested and try to get just one port working first...as for color: red =+5, green D+, white D- and black ground......if they wired it proper

Thank you for the replies!
Actually I am not sure about the pinout suggested and orientation at all, sorry!
How can you tell they are inverted? I do not see numbers on the board.
I tried both orientation with no luck,
maybe the order of pinout is not standard also?
Or maybe the usb implementation is so old that nothing works there anyway?

Of course the pin are present, I have not soldered anything, but in my past search for help Jan S. shared a bios with unlocked features like USB initialization. Should be here in the forum.
Once I am back home I will share pictures of the port and verify the southbridge.

Mamba wrote on 2023-09-10, 12:45:

Thank you for the replies! Actually I am not sure about the pinout suggested and orientation at all, sorry! How can you tell the […]
Show full quote

Thank you for the replies!
Actually I am not sure about the pinout suggested and orientation at all, sorry!
How can you tell they are inverted? I do not see numbers on the board.
Of course the pin are present, I have not soldered anything, but in my past search for help Jan S. shared a bios with unlocked features like USB initialization. Should be here in the forum.
Once I am back home I will share pictures of the port and verify the southbridge.

1st: use a multimeter to determine where is Ground, to be sure 100%.

In the picture:
on the top right corner you can see a "1" (I didn't notice until now... ); the trace that goes to it is huge and thus probably +5V, it then goes down (bottom left), from there you can deduct that after +5V you have data - (sbd-) follow by data +.

So here attached the USB area.
How can I test the pin with voltmeter?

And here the southbridge.

If you look at this site you'll see two examples of eight pin USB ports. You need to measure the +5 volt pins to determine for sure which yours is - get it wrong and power up with a ground wire connected to the +5... not good. Set your meter to measure DC voltage, and carefully measure the pins, making sure to not accidentally ground the +5 when doing so.

https://web.archive.org/web/20050830011044/ht … le_assembly.htm

SU903 supports USB.
Sometimes there are additional components on the mainboard in the signal lines like resistors (about 22R) and capacitors that might be missing when the USB header was not populated.
You can check each of the 4 lines for continuity (Ohmmeter) to make sure all lines are connected to the southbridge correctly.

majestyk wrote on 2023-09-10, 14:43:

SU903 supports USB.
Sometimes there are additional components on the mainboard in the signal lines like resistors (about 22R) and capacitors that might be missing when the USB header was not populated.
You can check each of the 4 lines for continuity (Ohmmeter) to make sure all lines are connected to the southbridge correctly.

I can check but I am far to be an expert, what setting should I use on the voltmeter and where to put the red and black probes?

Here is a video that covers how to measure DC voltage with a meter. https://twitter.com/JennyChachan/status/1700743568179241293

What I meant was if +5v supply and ground are confirmed and the BIOS supports and enables USB and USB still does not work it´s useful to check if the datalines are connected to the south bridge. Therefore you neet to set your multimeter to "resistance" or "ohms" (2K range).
Then you start with pin 142 at the south bridge and mesure the resistance between this pin and each of the 4 data pins of the USB header. At one pin you should measure a resistance of zero 0r 20-47 ohms. Then you rinse and repeat for pin 143, 144 and 145.
Each time there must be a zero (or low) resistance to one of the header pins.
If this is not the case there are probably some missing resistors somewhere in between.

Unbelievable….
I was able to run XP on the dinosaur with ps/2 ports populated of course, just to see if the usb ports were detected and BAM!!
Yes and no…

They are but with a error mark:

“Your computer's system firmware does not include enough information to properly configure and use this device. To use this device, contact your computer manufacturer to obtain firmware or Bios update. (Code 35)”

From digging on the internet:
This error message is displayed when a device does not have an entry in the BIOS MultiProcessor Specification (MPS) table. You can only see this error message on MPS-capable systems. This behavior usually indicates a BIOS bug. This is particularly prevalent on MPS systems with multiple root PCI buses.

Guess this is why no usb card works here, not even usb of the chipset itself???
How can be possible that no one made a decent bios for this beauty??

That´s probably the case!
A lot of more modern PCI cards don´t work or don´t work properly on this board.
This BIOS supports SMP and everything, maybe they snatched some tables and data to make it fit.

As long as this issue isn´t sorted you don´t have to bother about the continuity of the data traces of course.

I once had a PCI USB card working on the 586-DX - I think it had an Acer or VIA chip. But then I added a NIC and sound and ended up in IRQ hell as usual.

From the manual and the unpopulated header i came up with the same pinout as Nexxen.

I hope that Jan can help you sort out that BIOS issue. It seems wrong that my super cheap PCChips M520 (VX chipset AT) has working USB and this motherboard doesn't.

DerBaum wrote on 2023-09-10, 18:58:

From the manual and the unpopulated header i came up with the same pinout as Nexxen.
IMG_5257.jpeg

But you made it Italy's flag 😀
Nice touch 😉

Repo Man11 wrote on 2023-09-10, 19:44:

I hope that Jan can help you sort out that BIOS issue. It seems wrong that my super cheap PCChips M520 (VX chipset AT) has working USB and this motherboard doesn't.

Hope he can…