Hi, Greg.  Here is my suggestion to boot up Your MAXINE.

>> 0: PMAG-JA  DEC        V5.3A     TFCO  (CX -- d=8,24)
>
> Yes, I know they are not supported by X11Rx.  Does this possibly mean
> that they don't work as a console either under NetBSD?  Can I remove the
> card possibly?

Your unit has unsupported optional TC video card on TC slot 0.
Because it's unlikely for us to have PMAG-JA support in near future,
you should give up to use it with your unit.  Pull it off.  I think
it's a safer way you go, I think.

You have now two steps to boot it up.

1. use serial console for TFTPboot, and install whole NetBSD on local disk
2. then, switch console to MAXINE internal video circuit

I learned MAXINE can not complete netboot procedure with video
console.  (Jonathan already has some guess of the cause).  So, you
have to use serial console hooked up MAXINE serial port for TFTPboot.

* Your display unit is hooked up with CX video port.  With the PROM
  prompt >>, type a command "printenv", and record all the information
  it displays.  You might need to use it later to reset your unit to
  original condition.

* Hook a serial terminal (anything you have) . 9600/NP should be fine.

* Type "setenv console s" with PROM prompt.  It resets PROM, and then
  switch system console to the serial terminal.  Change will happen
  IMMIDIATELY, so you must have a serial terminal hooked up correctly
  before you type it.
 
* Now you should see PROM console messages on your serial terminal.
  Type "printenv" again, check and record what was changed.  Two
  variables "console" and "osconsole" have been altered.

* Try "boot 3/tftp", and see what will happen on the serial console.
  you will eventually get;

  boot device: <unknown>
  root device:

  on display, and your serial input is available on the root device
  selection prompt.

Next, you can step forward NetBSD installation.  Frankly, I'm not sure
what is the best (simple, error-proof) way to do that with current
implementation of NetBSD/pmax.  I guess we should have nfsnetbsd.ecoff
(1.2G) image, and all of NFS netboot environment are completely
prepared before installation.

* When you completed whole NetBSD/pmax installation (beware, there are
  many pitfalls even if you are familar with UNIX installation process,
  but I have little space to write them all here), and you are confident
  you've done well, halt the unit and get PROM prompt again.

* Type "setenv console 0".  Your unit now uses MAXINE internal video
  circuitry.

* Turn it off, and pull now defunct optional CX TC card off from slot 0.

* Hook a display up with integrated video port.  It requres "1024x768x8
  72Hz capable display."   It's possible you can not re-use the origial
  display formally connected with CX port.   In that case, grab a
  contenporary "multi-sync SVGA" display with *BNC port*, and hook it
  up.   It worked for my case.  My unit has VRT19 19" color display for
  HX optional TC video card, and it could not sync with MAXINE internal
  video port.

* Now you should have fully working MAXINE system with NetBSD/pmax.
  MAXINE internal video is recogized as "xcfb" framebuffer, and X11R5
  server can handle it (comment; I've never use the X server with xcfb)

Hope this help you.  Your way might vary depending on holoscope or your
knowledge.

Tohru Nishimura
Nara Institute of Science and Technology