The PC Card also doesn't care about sense code DIP switches as the onboard SVGA controller has no concept of them.
I can't speak for the Houdini II card, but the Houdini I card definitely pays attention to the sense code. It's fed into the 26-pin connector going to the card. I'd be shocked if the Houdini II behaved differently in that regard.
If I boot up with DIP switches 145 (
640x480@66.7Hz) the PC Setup control panel shows this:
When I boot the PC with this configuration I get a black screen on my monitor and my Epiphan AV.io capture card. My monitor says the signal is out of range. The AV.io claims it's an interlaced 1024x768 signal (WTF?) but shows a black screen. I also tried 1467 just in case it was a weird sync issue but same problem.
If I boot up with 235 (VGA) instead it shows this:
In this config I get good video. Interestingly the Epiphan card says it's 800x600, but my monitor says it's 832x624. Seems like it's picking Apple 16" even though it says VGA...
There's definitely some funny business going on with the video signal though. The above tests were with one monitor. If I switch to two monitors (145 on Mac, 235 on PC card) then the PC Setup control panel defaults to VGA but also lets me select Apple 16".
In this case I am getting normal VGA 720x400 instead (with VGA selected).
If I pick Apple 16", it goes back to the 832x624@75Hz signal instead, again mistakenly called 800x600 by my AV.io.
What exactly does all this all mean? I dunno for sure. What I can say is the card (although admittedly Houdini I in my testing) definitely detects the sense code as well as whether the Mac side is plugged into the crazy cable. So a no-video situation could definitely be caused by VGA adapter switch settings. For what it's worth, my random no-switch VGA to Mac adapter seems to be hardwired for VGA mode and it works fine too.
BTW, I noticed that the control panel's display settings don't reflect my changes to the DIP switches unless I power the whole machine all the way off and back on. A reboot doesn't cause the control panel's detected value to change. This might mean the same for the DOS card's display logic too. So it might be wise to change the cable setup only when powered off just to be 100% sure.
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Still I am not able to get picture of the PC, seems like the monitor receives a signal which it cannot take.
I'd definitely recommend trying combination 235 (or 2367, depending on the monitor's sync capabilities) on the 10-switch adapter. The Mac supports it, and it causes the PC card to output something that seems far more compatible than what I saw with the
640x480@66.7 mode.
Also, I can't speak for Houdini II, but Houdini I doesn't support sync on green. So you definitely need switches 5 or 67 enabled (not all 3 though). In fact, the easter egg you get by command-clicking the version number even provides a way to disable sync on green on the Mac side because the Mac side supporting sync on green and the PC side not supporting it caused problems with some monitors back in the day.
It's possible Houdini II works different from my experience with Houdini I...but I doubt it's
that different from a display standpoint. Just thought I'd share a few of my tips since I've been playing with this setup recently in my 610 and have experienced lack of video myself with some adapter configurations.
The PC is booting with the "TinyBootDisk", and PC Setup says: "PC running"! Still I am not able to get picture of the PC, seems like the monitor receives a signal which it cannot take. Do you think, that this would help? https://www.worthpoint.com/worthopedia/nec-multisync-universal-apple-1829658407
