Subject: Re: System error 0911 on IIgs
From: Rubywand <rubywand@swbell.net>
Date: Mon, Nov 30, 1998 15Ç29`
Message-id: <36631C3F.96CC17FA@swbell.net>

Glenn Fisher writes ...
> 
> Sometime when I power on my IIgs, I get a
> "System Startup error 0911"
> Can anyone tell me what this means or point me to a URL where I
> might find out what it means.  I do not have a IIgs manual.

 ....

     The Apple IIgs Hardware Reference and The Apple IIgs Firmware
Reference are good to have; but, they do not cover this problem. Nor is
it mentioned in the tech notes.

     The source of the 0911 error (0400 error on the ROM-00 GS) was
nailed in a 1988 issue of Computist. Basically, one of the two major ADB
IC's malfunctions and this malfunction is temperature dependent.

     As Paul observes, reports vary a bit regarding specifics. My
experience has been that the IC bombs over a range of relatively low
room temperatures. On our original motherboard, the bombs first became a
bother during summer when everyone in Houston runs their air
conditioners and rooms are often cooler than normal. We added a System
Saver GS. Its fan cooled the GS interior and the frequency of crashes
_increased_.

     We essentially eliminated 0911 crashes by placing a 12V panel bulb
(bullet-shaped, about 50ma or so) on top of the temp sensitive IC and
enclosing it with duct tape to form a mini-oven. The bulb was powered
from the +12V pins near the back left side of the motherboard. Anyway,
tests showed that crashes went from 3-4 per day to just 4 over a
two-week period-- all of these crashes were at or soon after power-up
before the bulb had a chance to warm things up.

     The mini-oven fix is not difficult to try out. It's been a long
time (we finally swapped-in another motherboard), but I'm pretty sure
the actual culprit is the ADB Glu IC (a square IC near the right front
at the I-12 position on the motherboard).  The other posibility is the
smaller ADB Controller at the I-14 position.



Rubywand