From: hagberg@ccit.arizona.edu (HAGBERG JR, D. J.)
Newsgroups: comp.sys.mac.hardware
Subject: Followup: MacIIsi not Shutting Down
Date: 1 Oct 92 20:12:00 GMT
Distribution: world,local
Organization: University of Arizona
News-Software: VAX/VMS VNEWS 1.41

This is a followup on my posting about a client's Mac IIsi turning itself 
on at weird times of the night, and finally escalating to where it would 
do a "restart" if you selected "shut down" in the Special menu.  Hopefully 
this posting and the followups will help others troubleshoot a similar 
problem if they encounter it.

>        I just got a call from a client who's having a very strange
>problem with his IIsi.  For the past couple days it's been turning
>itself on at random times of the night.  Now today we went through
>some troubleshooting when the problem escalated to the point where
>it will only "restart" if you do a "shut down".
>
> The following were checked:
>
>        1) Disconnected the keyboard and cable to see if the
>           cable or kbd went haywire.  No change.
>
>        2) checked to see if the "power" button on the back of the
>           computer was stuck in for some reason.  It wasn't.
>
>        3) Replaced the Finder to see if the fmnu's were screwed
>           up somehow when I added command-key equivalents.  No
>           change.
>
>        4) Turned off all INITS and disabled MacPassword.  No
>           change.
>
>That pretty much left me with the feeling it was a problem with the
>switching circuits in the power supply, and probably meant getting
>a new PS (I think it's out of warranty).
>
>My question is this:  Has anyone else experienced this problem and
>solved it by replacing the PS?  Is is just a simple relay that's
>been fried?  His computer is in an industrial building with flaky
>power, but he does have an isolated circuit for the computer, and
>has a UPS/surge prot. for the frequent power failures in the area.
>
>Any ideas?
>

Following are the more interesting replies I received.  Some people suggested
I check the power switch to make sure that it wasn't in "auto-restart" mode, 
and to try swapping the keyboard. Both were good suggestions and should be 
a first step for anyone troubleshooting this type of problem, but I had 
already checked those.

The repair person I talked to at Computerland said she had seen the problem
before.  Sometimes it could be caused by the power button not being properly 
attached to the motherboard, and sometimes the whole motherboard needed to be
replaced.

One other person on the netnews suggested the problem might stem from the 
motherboard --> power supply connector coming loose, and he solved his problem 
by pushing the motherboard back into the connector.

-----------------------------------------------------------------------------

From: David Faust  tigger.freezer.cns.udel.edu

Boy, that does sound familiar. I had the same problem with my ci. They changed
the power supply and that didn't fix it. So they ended up replacing the mother
board. That fixed the problem. Good luck.

-----------------------------------------------------------------------------

From: Paul Siu  upsiu@mcs.drexel.edu

Hmm... Try swapping in a different monitor.  I seem to recall Apple recalling
monitors a while back because of some electrical problem that may cause the
Mac to turn off.  That's probably not the problem, but it's worth a try.

-----------------------------------------------------------------------------

From: Jim Daniels  jwdanie@sandia.gov

I also had this problem with my si, it would randomly turn itself
on and had problems shutting down.  Unlike the posted solutions,
however, my problems were only solved when the logic board was 
replaced (under warranty).  Hope yours is a simpler fix!

-----------------------------------------------------------------------------

From: Dave Platt  dplatt@ntg.com

I had a similar "ghost in the machine" problem with a Mac II, a few
years ago.  It turned out to be caused by moisture condensation, which
was creating a current leakage inside a Kensington trackball... enough
current leaked between the "power-on" and "ground" wires to trigger the
very sensitive power-up circuit (only a few micro-amperes of leakage was
sufficient).  I fixed the problem by locating the offending PC-board
traces on the trackball and putting a dab of clear nail-polish over
them... this blocked off the moisture.

The Mac II was subject to this problem because it sat overnight in a
room which received little or no heat at night (we closed the door to
the den to save fuel).  In the morning, the door was opened, and
warmer/moister air from the bedroom and bathroom flowed into the den,
and then triggered condensation inside the Mac case and inside the
trackball.

-----------------------------------------------------------------------------

I hope this helps anyone else who has a similar problem in the future.

"I see the hand of man arise,       -=-   D. J. Hagberg
 with hungry mind and open eyes."   -=-   hagberg@ccit.arizona.edu
         -- Neil Peart, 2112
Newsgroups: comp.sys.mac.hardware