Finally had time to work on this again.
Ok, so both machines have Cherokee power supplies, and both PSUs work (in the working machine). The non-working machine powers on immediately from connecting the mains cable and there is either no output (serial) or continuous output of dots (serial) and no display (VGA+keyboard+mouse). I've tried to re-seat all the cards, and also the RAMs. I guess I should also try removing all RAM (will it boot with none or should I leave some in?) and perhaps remove and re-seat the CPU module as well? Or would this be a crossbar or motherboard issue? Would it be safe to swap parts between the machines or would a bad crossbar or motherboard damage eachother?
Yesterday I finally got the 13W3-VGA adapter and I booted the working machine with display, keyboard and mouse. There is a working IRIX 6.5 installation (with no passwords at all!).
At least I have one working Octane now
Here are the specs of the working machine (the one with orange octane on front panel, and the one with the PCI card cage at the back):
Hostname (which I cropped out) gives a hint of the previous owning company and there are some print/video project -sounding directories on the disk (or at least backups of projects). Couple of short local TV ads as video files. File dates indicate this was used sometime 2003-2006
There are several NFS shares it tries to connect at boot, and shutdown seems to halt at unmounting something as well. I'll need to hook this up to a network (if I can figure out how to configure it...) and pull out any interesting stuff and then I guess I'll do a clean install.
This was literally my first time clicking around the IRIX desktop but I really like how it looks and feels! (I just wish the fans wouldn't be so loud!)