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By the way, the reason for the 8086 VDU card freaking out is because of my flawed initial implementation: I had ROM mapped at both F0000 and 30000 so that the boot vector could be fetched.

I've switched to using a read tap which unmaps F0000-FFFFF as soon as the boot vector is fetched, and the VDU card now appears to be functioning more or less normally.

When the first vsync interrupt comes in, the VDU card looks at F8000 (which is located in the half-meg upper window into the Multibus address space). If it's zero, it simply sits in a tight loop, reading the location.

Since I had the boot ROM mapped in that range, it was seeing a non-zero value, then completely freaking out due to what would apparently be invalid data in that range.

So yes, at this point I suspect what's needed to move forward is to get the Z80 up and running.

I actually have a crazy idea. It's not that the Z80 boots from address 0x1800, it's that it fetches from there.

in this case z80 ice will help. I am preparing a stand.

So the Z80 ICE is connected, the processor is running at a clock frequency of 5 MHz.
I confirm the Z80 from the zero address is the code that is in the ROM with # 1800 address. until # 0800 in and then repeating this page of memory at all addresses # 0800, # 1000, # 1800, # 2000, # 2800, # 3000 and up to # F800.

That's excellent info, thanks!

I'm currently at work for the next 2 hours or so, but I'll get back to you after that for more information about the ICE commands. Mainly, I want to see if I can manually invoke IN opcodes in order to see what the mapping RAM defaults to on reset.

I got a great LABTAM V32 system!
It consists of a main processor board on CPU - NS32032, MMU - NS32082, FPU - NS32081, 2 Megabyte RAM.
Additional one or two RAM board with 6 Megabyte.
Four board with CPU - 8086, MC6845, 4 terminal port (The board is the same that we are currently implementing in MAME)
Controller SMD HDD - INTERPHASE SMD 2190
Controller 1/2 inch TAPE with PERTEC interface - Xylogics 472
I also dumped the BIOS from the NS32032 board. It looks like there is also support for Booting from the Z80 board (FDD + MFM HDD).
https://www.dropbox.com/s/p81ok1yo6nej4l4/20210622_230741.jpg?dl=0

That's interesting! Do you have any pictures of the boards and/or documentation? Those three ns32k family chips are all emulated pretty well in MAME now, so adding this system should be doable.

Unfortunately, there is no documentation for this board. There is documentation on boards for i8086 and Z80 which I work with this board.
https://www.dropbox.com/s/qgw4hk47xmv30js/LABTAM%203000%20System%20Manual.zip?dl=0
I will take photos in good resolution a little later, while there is only this photo.
https://www.dropbox.com/s/p81ok1yo6nej4l4/20210622_230741.jpg?dl=0
I can also trace the connection on the board if it is necessary to understand some parts of the circuit.

This is how the board looks like with the Z80 ICE.

Found some information on the NS32032 board.