Need Help with Houdini II Cable Project - DOS Compatibility Card Y Cable Replacement

[SteveHere]

I've finally started on a project that's been on my list for over a year. I got a 6100 with a DOS Compatibility card from an estate sale, but it had been separated from the Y Cable. This is a common problem and so the cables are hard to find and expensive. Previously I've duplicated the Y cable for the Apple IIe card, and so I was planning to do that again for the DOS Compatibility card. This being only my second circuit board design and a more complex project my first iteration is not working so I'm here for advice.

My design for this cable is based on the pinout available online here....
https://computers.popcorn.cx/apple/powermac/6100/cable/
Has anyone in the community built a cable based on this design? I'd like to verify that this information is correct.

Here's my card so far...

When I start the DOS machine, video does appear on the output port so that part of the design is working as expected, but video from the Mac is not passing through the card so that part of my design must have an error. (Probably self-induced)

If the large plug is disconnected, would we expect the Mac video signals to pass through to the Monitor? I think that the DOS Card must be connected in order to pass through video, but since I don't have a known good cable I can't confirm.

Is it possible that the cable is not entirely passive, that there are some diodes or other components embedded into the cable?

If I can get this design working, it is my intention to Open Source this design and put it up on my GitHub. Thanks in advance for any help / advice that owners of the Houdini II cable can provide!

 

[Androda]

Based on my understanding, it's expected that you need the DOS card to pass through video. DOS card is basically a switch, and outputs either the Mac video or its own signal.

It's kind of an awkward setup, where Mac video has to be passed into the DOS card and then the card decides which video to output.

Connectors like these bite me every time. Have to carefully count pin numbers, trace to the footprint position, and ensure that the correct style of connector is chosen (pins or socket) for your CAD program to show the pins in the right order.

Thanks for working on this! Do we know if the Houdini 1 and 2 use the same cable? I have the card but am missing the cable for my Houdini 1.

 

[SteveHere]

Thanks @Androda. Going back and looking at my design based on your feedback, I changed a connector from male to female in order to make the cabling work better forgetting that this will change the order of the pins! I'll go have a look at that.

I've done a bit of poking around on the Internet to see if the Houdini and Houdini II cards / cabling are identical, but I can't find a conclusive answer that I can back up with multiple sources, sorry about that! Maybe someone else will remember?