I checked the manual, and I think it's a rather particular card, the one you're missing.
I photographed you, the pages where there is the description, I don't know if it can be useful to you in some way, but perhaps it is possible to see which VGA pins go to the connector, however I don't think it will be easy to understand something about it, without the help of someone who understands enough.

multimeter in continuity mode and datasheet for s3trio64v+ page 17, pin 150 vsync, 149 hsync, 168 red, 171 green, 172 blue.
no idea what the other vga pins are on the s3 chip.

http://www.bitsavers.org/components/s3/DB018- … rator_Jul95.pdf

edit: oh yeah and needle tip probes 😀

PC@LIVE wrote on 2024-04-25, 19:52:

I checked the manual, and I think it's a rather particular card, the one you're missing.
I photographed you, the pages where there is the description, I don't know if it can be useful to you in some way, but perhaps it is possible to see which VGA pins go to the connector, however I don't think it will be easy to understand something about it, without the help of someone who understands enough.

Thanks for your reply. I found that document, too but unfortunately there are no information about the pinout 😉

weedeewee wrote on 2024-04-25, 20:06:

multimeter in continuity mode and datasheet for s3trio64v+ page 17, pin 150 vsync, 149 hsync, 168 red, 171 green, 172 blue. no i […]
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multimeter in continuity mode and datasheet for s3trio64v+ page 17, pin 150 vsync, 149 hsync, 168 red, 171 green, 172 blue.
no idea what the other vga pins are on the s3 chip.

http://www.bitsavers.org/components/s3/DB018- … rator_Jul95.pdf

edit: oh yeah and needle tip probes 😀

Jipp, thats my plan now. I will share my results next few days.

Anybody out there who has knowledge about what is needed to the circuit between vga connector and the GPU? Maybe parts for decoupling or coupling to ground of the connector pins?

Best regards 😉

JF_Sebastian wrote on 2024-04-25, 22:35:

Anybody out there who has knowledge about what is needed to the circuit between vga connector and the GPU? Maybe parts for decoupling or coupling to ground of the connector pins?

They should be connected directly to the GPU with 75 ohm resistors to GND for the R, G, B lines. Not sure what impedance the HSYNC and VSYNC lines use.

Not that it helps much, but this is about the best pic I could find of the breakout card (seems to differ from the manual where not all the ports are hardwired). From the traces it looks like the (approx) inner 16 pins on the m/b connector are for vga.

There are a few posts elsewhere from the late 90s asking the same pinout question - none got an answer (seems Soyo were no help at all!)

Thanks to all your replies an helpful information! I'll let you know as soon as progress is made 😉