Iris 2400 question

[Bill HEELAN]

   We have a couple of old Iris 2400's here just gathering dust, and I would
   like to use one of them as colour display.  I chose to (try to) revive
   the one that I knew worked most recently.  The problem is that while
   booting, about the time when it finishes the fsck of the root partition
   the screen quickly fills up with white blocks and the machine hangs.

   The machine contains the boards:

      slot  1:   CPU
      slot  2:   I/O?
      slot  3:   I/O?
      slot  4:   <empty>
             .
             .
             .
      slot 15:   <empty>
      slot 16:   memory
      slot 17:   memory
      slot 18:   graphics?  largest of the boards (in length)
      slot 19:   graphics?
      slot 20:   graphics?

   I think at one point someone removed and replaced one of the memory
   boards, so its possible that the switch settings got mixed up.  Also,
   I can't find descriptions of the boards in any of the documentation.

   I realize that there is quite a lack of information here, but does
   anyone have hints, suggestions or references (e.g. switch settings,
   etc.)?

                                                      - Bill