I think they used long lead ISA sockets and bent those 10 to fit in those holes. Look for ones designed for wire wrap, they have .5"+ long leads and you should be able to bend them 90' then about 1/8" in bend again 90' to work.... just my opinion.

What is your purpose in adding a second ISA slot?
If in order to use multiple ISA devices, why not try this.
Short on ISA slots? Try this.

Thanks for the link, but I’ve already read this (and related) threads. The purpose is to have two ISA soundcards in the system and not just for testing. So the ISA riser/backplane solution is not so convenient for me because it will require case modification and limit case selection. I’m considering it as a last resort option.

Horun wrote on 2024-01-10, 03:30:

I think they used long lead ISA sockets and bent those 10 to fit in those holes. Look for ones designed for wire wrap, they have .5"+ long leads and you should be able to bend them 90' then about 1/8" in bend again 90' to work.... just my opinion.

It’s an interesting idea! But where to source these wire wrap ISA connectors? I can’t just rip them off from some spare motherboard because the leads will be already shortened.

Never mind, I’ve found wire wrap ISA connectors on the Digikey. Unfortunately, judging by the connector blueprint, the connector has very limited space underneath it - if I want to make a 90 degree bend, the bend curvature radius should be minimal for the bent lead to fit under the connector (I.e. fit in the way that connector height won’t increase) and with such a small radius the lead could simply break.

Maybe someone from the community has two ISA slot P3B-F and could check if the second ISA connector really has bent pins underneath it?

I have a 2 Slot PB3-F. If i get chance i will try and get some pictures for you.

Bancho wrote on 2024-01-10, 08:33:

I have a 2 Slot PB3-F. If i get chance i will try and get some pictures for you.

Thanks! BTW, judging from the Wikipedia photo, the second ISA connector slightly differs from the first connector in design. I think it was made by different manufacturer. And it has some markings on the side, but it’s difficult to read them in this photo.

nevermind.

I got some pics the evening. Its too hard to capture how the legs are, but the bottom row of legs on the isa slot go inward at an angle. Board is a V1.04.

I tried my best to get a pic that shows how the pin sits in the slot.

Wow. So looks like they are really bent, though not at 90 degrees. And I think they are factory bent by the connector manufacturer - there was no point in using connector from different manufacturer if Asus could it themselves. Probably it’s a custom order but we’ll never know because EDA Inc. is long time defunct.

Well, I think the next step would be to buy a bunch of ISA connectors and try to bend the leads in the same way. And design a testbed PCB. And make a bending template.

Anyway, it should be a fun project. I’ll keep you posted but I’m a slowpoke (and have other work to do), so don’t expect any updates soon.

Bancho, thank you very much for the photos!

I got your PM, and I've only just had a chance to get to the motherboards.

I've taken a couple of photos of the two-slot P3B-F. Hopefully, these can help

janskjaer, thanks! Additional photos of this great board are always welcome 😀

I think it must be something like isa 98 pin with 90 degrees:

Or we can try to cut some plastic: