IIGS Monitor problem...Help, Please

[Tom O'Neill <tdon@delphi.com>]

While tickling the keys two nights ago and dling my e-mail from Delphi
using Spectrum, there was a slight "poof" sound.  Immediately, the screnn
went from text to a checkerboard pattern, multicolored...red, green, and
blue, I think...and it began flipping about once or twice a second...scrolling
upwards, that is.
 
I shut it down after first trying to reboot (control, open apple, reset)
and the colors changed somewhat to include black and white interspersed
with the colors mentioned above.  Upon restarting, the screen came up
with nothing but black and white rectangles, some of them irregular
lengths and widths.  More importantly, I believe, there is no response
to the three-fingered salute whatsoever.
 
I've made and broken connections with the keyboard several times, but
haven't brought myself to open the case yet and look for damage to a
chip or the PS.  Power does get to the floppies and to the monitor,
but there is no control.
 
Is there anyone out there who can make a diagnosis as to what I might
be facing?  This is a ROM 01 machine with a Zip 7/8k, Supersonic stereo
card, PCT aboardbut not in use, Super/drive card, Apple High Speed SCSI,
8 Megs of ram (4 on a CV Tech card and 4 on a piggyback card), and
both a Quickee and a Lightning scanner card filling the slots.  There are
both a Quantum 170Meg external and a daisy chained 40Meg external, and
both of these are powered separately, so don;t serve to overload the
system.  Both still spin up independently, too.
 
Work doesn't permit me to get into it until this weekend, but I may be able
to open the case tomorrow night and look around.  Meanwhile, any suggestions as
to what I might have done?  Anyone see a pattern like this before?
 
TIA,
Tom