> The -3/150, as far as I can tell, does not drive anything out the video
> connector at all - the display is solid black and stays that way, even
> if I flip the switch to DIAG mode and press e for echo mode when the
> self-test finishes.  (That machine has no other framebuffer.)

Check EEPROM settings.  Console can be on either serial port, bw2 or
cg2.  You will get a blank screen unless the setting is correct.

> My questions, then, are (1) is there any reasonable chance of getting
> the -3/150 to drive its video connector? (2) can the monitor be
> adjusted to run 1600x1280, and would it hurt it to do so? and (3) when
> I boot NetBSD on the -3/260 (using the cgtwo it also has for console),
> it reports the bwtwo as 1152x900, why?

The monitor cannot be tweaked for 1600x1280.  That's a different monitor
altogether (available from RNA for $150 more than the 1152x900 monitor).

The 1152x900 again probably comes from the EEPROM.