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Re: Reducing Noise on the IIgs (Fatal System Error 0911)

Rubywand wrote:

"Matthew S. Carpenter" writes ...


Hello,

I recently upgraded my TWGS accelerator with a 32k cashe card.  After
doing this My IIgs has been giving me Fatal System Error 0911 with a
fair amount of frequency when I try rebooting the IIgs to different
drives and sometimes when I try to go into the control panel.

After looking it up in the CSA2 FAQs I think it's likely due to noise
problems or dropped voltages.
<http://home.swbell.net/rubywand/Csa2HDWHACK.html#005> I have in my
Apple ROM 01 IIgs: a LanceGS card[2], a TWGS[3], an Apple High Speed
SCSI card[5],a superdrive card[7], and an 8MB Serius RAM card.  I've
already done the power supply mod as explained here
<http://home.swbell.net/rubywand/Csa2POWER.html#005> but the errors
persist.

I was going to try adding wires to make the path from the power plug to
the slots on the board fatter but I don't think I'd be able to do it and
not have problems with shorting or crimping from supports in the case.
<http://home.swbell.net/rubywand/Csa2POWER.html#006>.



 ....

     One check would be to try running without the SCSI, Superdrive, and
LanceGS cards. If the 0911 errors disappear, then power problems look fairly
likely. Since you've fattened the PS leads, the PS itself would be suspect.

     If you measure the +5V voltage on the motherboard, it would be useful to
know if removing the boards makes a notable difference-- like around .25V or
more. 
     Despite the above, getting 0911 errors with any consistancy during the
keypresses you mention seems to indicate a flaw somewhere in ADB hardware.

     If your IIgs is a ROM-00 model which was upgraded to ROM-01, you may have
a borderline ADB IC-- probably the ADB GLU. Just being in a room which is
cooled during the summer could be enough to trigger a sudden rise in 0911
errors. 
     A pretty good fix for a temperature sensitive ADB IC is described in the
FAQs at http://home.swbell.net/rubywand/Csa2HDWHACK.html#005 .

     Another thing to check is the connectors at your KB. Those tend to work
loose and develop breaks between the connector and the KB circuit board. A poor
ground connection might make the ADB line more susceptible to noise.


Rubywand
Well, I put everything together again... at first I didn't get any errors... I booted it after putting in every card.... I got all cards put in and then put in an extra one I got in the mail.... it seemed to be working well so I just put it to probably a keyboard connection problem.
Then I got called away to put away laundry and left it on. When I came back I rebooted it and got a 0911 error. I rebooted again and got the 0911 in the middle of GS OS bootup. After that I shut it off for the night.
The next day I messed around with it a little... installed spectrum and SIS.. set them up.... was looking around....pretty cool.... then I went to fill in some forms on a page....on the 3rd entry box the computer got stuck on "h" on repeat..... (hhhhhhhhhhhhhhhhhhhhhhhhhh...) I unplugged the keyboard and it didn't stop. I hooked it back up and closed Spectrum....I opened up hermes and it filled the window up with 'h's.
After that I shut the IIgs down, unhooked my Apple Extended ADB keyboard and plugged in the junky Apple keyboard II I had on my Mac SE... So sometimes the keys get stuck down and I have to pry them up with a house key...and sometimes the keyboard doesn't send my keypresses....but now I don't seem to be getting 0911 errors anymore so far... and I've done a lot of rebooting to load disk images I've been putting on flopies.
I really need to get a better keyboard.... I'd really like to get the stock keyboard that came with the IIgs. 

Thank you... I really should have tried that first.

-SP.
"Oh, if only I had a... um... oh whatever."
<http://homepage.mac.com/superpsycho/index.html>