video problems: debugging help

[jclose@potomac.ads.com (Jeff Close)]

   Date: Mon, 11 Feb 91 09:52:39 MST
   From: drstrip@gnome.cs.sandia.gov (David R. Strip)

   ...
   My dying 3645 refuses to send video to the terminal (or so it seems).
   I have eliminated the following possibilities (usually by swapping parts
   with a 3640 next to it):
      monitor
      monitor cable
      FEP board
      I/O board
      paddle card (is this the right name for the small card in the back
		   that has the video output?)

   The machine appears to be alive, since i get nice random patterns on the
   monitor that disappear for a moment when I blindly type reset video.

   What else can I pull/swap to try to isolate the problem?
   ...
  
David,

Have you done anything since reboot, or did you boot differently, by
any chance?   What I'm getting at is that it sounds somewhat like the
behavior one can get if the wrong monitor driver is loaded.  You might
try the FEP command Set Monitor-type [M or P].  If this doesn't
correct it, set it back quickly, since I don't think it's too great
for the monitor to have it running with the wrong one.

Jeff