Error 0911 'Cure' (was Re: Error with GS)

[Rubywand <rubywand@swbell.net>]

Josh Seymour writes ...
> 
> Help!  When I do the internal diagnostic it gives a system bad : 09010001
> And when I boot from my power drive (never had a problem before?) It gives
> a fatal system error : 911. I booted from my Q drive with no problem the
> second time (first time a fatal system error :911) ....


     Fatal System Error 0911 and Self-Diagnostic Test 09010001 mean the same 
thing: You are experiencing an ADB Controller malfunction.

     A guess would be that you are running a ROM-01 GS, probably a ROM-00 
machine which has the ROM-01 upgrade. If this is the first time you've 
noticed the '0911 problem, it is likely that this is the first summer you've 
owned and used this particular machine.  

     Fatal System Error 0911 almost always indicates a faulty ADB Controller 
IC. The failure mechanism was first identified and described in Computist 
#58 back in 1988.

     Many early GS's come with an ADB Controller IC which malfunctions over 
a narrow range of relatively low temperatures. Rooms are normally cooler 
during summer; so, this is when the error pops up most frequently. Some 
users first notice a plague of '0911 crashes after adding a System Saver-GS 
(which increases cooling).

    '0911 bombs can occur 'any time' but they usually happen at startup and 
when doing OpenApple-CTRL-ESC accesses to the Desk Accessories (CDA's, 
Control Panel, ...) menu. As the machine warms up, '0911 crashes tend to 
become less likely.

     The bad news is that there is no 100% fix except to replace the ADB 
Controller IC-- hard to do since it is soldered to the motherboard and, in 
any case, known-good replacements are difficult to find.

     The good news is that a very nearly complete cure is not all that much 
trouble. Since the problem is coolness, the cure is to tape a small 12V bulb 
(e.g. a 20-30 ma. panel light bulb) to the top of the ADB Controller IC 
(IC-19, a square IC near the right front of the motherboard). Use duct tape 
and try to enclose the bulb and IC in a kind of mini-oven. Run the leads 
from the bulb to the +12V Fan power pins near the back left area of the 
motherboard.

     The idea is to quickly warm up the ADB Controller IC. I used a scheme 
like this on our early GS and 0911 bombs dropped from 4-5 per day to 2-3 per 
week. If you can safely power the bulb via an external power module (e.g. a 
calculator or radio 'AC adapter') so that the bulb can be ON at least a few 
minutes before powering up the computer, 0911 bombs might disappear 
entirely.     


Rubywand