ACA500plus and ACA1233n

Hardware-wise, the ACA1233n appears to work. Did you update the ACA500plus menu system to the latest version?

Again, the hardware appears to be OK, as the menu is already executed by the 68030 CPU if the board is connected to the ACA500plus. I suspect that there is a piece of software in your installation that makes the computer "hickup".

Since installing a WB is so easy with the ACA500plus, please try making a fresh 3.1 install using the automatic installer and launch the system by pressing F1 (no special profile) with that freshly-installed CF card. Does it come up then?

What's the power supply you're using for the setup?

TBH, this does not make any sense. You say that the ACA1233n works fine in an A1200, so that part of the hardware is fine: ACA1233n is a subsystem of CPU and RAM. In other words: CPU and RAM are fine.

Now you're connecting it to the ACA500plus, and you're showing a guru message that says it's crashed in it's own memory (address 0x40029F00 is local to the ACA1233n). 'd have to look up what the B at the end of the error code itself means, but that should not play any role: You mentioned that this is a fresh install, generated by the installer of the ACA500plus (please confirm that you are not using any other WB install that you've written to a CF with your PC).

So at this point, I can only assume that either the CF card contains faulty software that may try to run FPU code where no FPU is installed, or that both power supplies that you're using have high ripple or under-voltage due to the additional load. Is one of the A500 PSUs the 4.5A type for the 5V rail (light-weight type)?

I can pretty much confirm you should use a 4.5A PSU (the 4.5A type that came with some A500s) for that setup. I used to run the ACA500 (old version) together with my ACA1233 (The older red version) and it would not boot using the 3A type A600/A1200 PSUs. I had to use the 4.5A variant. Mind you, this was before I had recapped my PSUs, but they were working.

ACA1233 in the A1200 would boot with a 3A PSU. The A500 + ACA500 + ACA1233 is more power hungry and would, as mentioned require the 4.5A PSU to boot.

It might be more related to that ATX PSU in this case...

Quote from DeckardThreepwood

checkmateA1500 plus case

Please turn to the vendor of that product for support. We do not support ill-fated designs that we've recommended against for YEARS.

The manual clearly says that the ACA500plus is built to be connected DIRECTLY to the A500 board. If you are trying to use it with an additional thing in between, you have personally decided to ignore our manual. Can't help you here; you're on your own.

I've tried to improve the Checkmate case, but my technical, totally factual warnings were actively ignored.

We deliver stuff that works by design. Making it compatible with things that work by accident would be a huge hassle that a) costs a lot of money and b) has no certain outcome (i.e. it still may not work reliably). You'd be pissed if you're among the persons who don't get a working system, despite a higher price - and you'd have every right.

The model of working products for a very affordable price point has been successful in the past. I don't intend to risk the good reputation of iComp for a low chance of compatibility with products of questionable engineering effort (or plain lack thereof). This is not a general "no" to cooperation - it's merely outlining the fundamentals of a possible cooperation: If it's engineering, I'm in.