There are two types of ISA passive backplanes, one with just ISA slots and power, the other has ISA slots, power and keyboard. You need the the first one.
I saw a website of a guy that used a old 286 motherboard with ram, cpu, bios, kb controller and chipset all pulled as his ISA test backplane (cannot find it now),
but you would want a board like: https://theretroweb.com/motherboards/s/acer-9 … 0-900-pb87011-3 where you can remove all that.
Or just buy one for ~$50+: example: https://www.ebay.com/itm/255910413783

Many thanks @Horun.
Currently the single board PC is used into a mainframe (it is a motion controller) and in fact is plugged into a backplane card which looks like what is on your second link. It contains 4 ISA slots, in some of which there are some extension cards.
Could it be as simple as finding an old ISA VGA card and plugging it into one of the free slots?

Yep, that should be all that's required. That's how it works with my 386SX advantech boards like this that don't have integrated video. Doesn't seem to matter too much which slot it goes in either

OK great, will try this and report back. Next challenge is to find a working VGA ISA graphics card; am guessing eBay is my best chance?
Are there any specs/types/else to keep an eyeout for when looking for such a card?

Any ISA graphics card should work to get a picture.
They should have 512kb to 2mb of ram. If you want higher resolutions you need more ram. For a 486 (dos/win3.11) 1mb is plenty.
I try to buy retro stuff not on ebay these days. The prices have exploded there.

I have lots of industrial CPU borads and they are pretty compatible.

If you have time and a little bit of luck you could get yourself a PC104 graphics card, wich gets extra coolness points in a industrial build 😁

Thanks @DerBaum;
how would you then connect that (cool) PC104 graphics card to my PC104 single board PC? Via the PC104 port I assume?

Loic74650 wrote on 2023-08-29, 20:24:

Thanks @DerBaum;
how would you then connect that (cool) PC104 graphics card to my PC104 single board PC? Via the PC104 port I assume?

Yes. You build a sandwich out of all modules you want in your pc. Of course you can mix PC104 connected cards and ISA cards on a backplane.
PC104 soundcards are basically not existing anymore (except of home made ones)...

I use the Industrial stuff more for experiments and fun then for real retro gaming. So i built myself some Industrial CPU card test stations out of old industrial equipment.
I should make a thread about the 3 that i built to maybe give others some ideas.

Loic74650 wrote on 2023-08-29, 14:35:

OK great, will try this and report back. Next challenge is to find a working VGA ISA graphics card; am guessing eBay is my best chance?
Are there any specs/types/else to keep an eyeout for when looking for such a card?

In my opinion the ISA VGA cards up on ebay are pretty cheap, but the 'known best' tseng cards tend to go for more. I've recently found it makes only a little difference, at least for Quake: Re: (ViewTOP) WD90C30-LR ISA VGA DIP switches: play DOS games at 90hz refresh rate
Just go for one of the later cards and you should get good performance.

These little ISA / PC104 single board computers are fantastic for testing out ISA stuff, here's one of my Advantech single board computers that's built up to be a full computer with video and sound, runs off a 12v power supply:

The 'case' is 3d printed and the PCB is my own design. I've not shared the ISA / PSU board, which is one I designed in EAGLE - sadly I've since lost access to EAGLE and want to make some changes before I share it. So it has to be re-done in Kicad

Wow that is a neat computer 😉
I am waiting for a cheap eBay VGA card, let's see if that does the trick (I only need a very basic display in order to set the bios parameters)
Greetings

Greetings all,
So I received an old VGA card, vendor said it works. But when installed in the backplane with the Lanner AP-40AHD single board PC and powered up, I don't get any video signal out of the VGA card. I have attached a few pics of my setup as well as the user manual of the single board PC, in case that helps with suggestions... Maybe some jumber to enable the video mode?
Thanks in advance
Loic

Is the ISA slot you put the VGA card in 8-bit or 16-bit?
If it´s 8-bit (only the longer part of the slot being present) chances are your VGA card won´t work. There are only a few ISA VGA cards that support both ISA versions.
You would need something like this in this case:
https://www.ebay.com/itm/385932205291?

Indeed, only the longer part of the slot is present on the backplane.
OK, back to eBay then, thank you

You could buy a 16-bit ISA backplane instead, but this will not come any cheaper, I´m afraid.

Thanks.
So my 8-bits single board PC would work on a 16bits backplane with a 16 bits video card?
Anyways I bought the card on eBay you recommended. Will report back!

Your SBC is 16-bit, so it will work wiith your 16-bit VGA on a 16-bit ISA backplane.

Pff ah yes, sorry, my ignorance

Loic74650 wrote on 2023-09-07, 16:13:

...I received an old VGA card...

You are lucky. I own exactly this graphics card. download/file.php?id=171759&mode=view
I can test it if its 8 bit compatible or if its a problem with the sbc.

And i can show you some cheapo 16 bit isa graphics cards that can be used in 8 bit mode.

I think the chances might be good, there are some jumpers for 16/8 bit BIOS etc, some marks are under a sticker.
It´s probably safer not to trust "auto detect".

Thank you @DerBaum, that would be awsome.
Note that I just acquired the VGA card advised by @majestyk (https://www.ebay.com/itm/385932205291)
I have also found a cheap 16 bits backplane with PSU, for the sake of testing various configs.
Finally, I have just received those replacement RTCs (https://www.ebay.com/itm/175360904323) which is originally where the whole issue started (loss of the BIOS parameters on the SBC due to dead RTC battery).
This resurrection is starting to cost me an arm and a leg !