Re: Apple IIgs random hardware crashing - any ideas?

[ToasterKing <toasterking@SPLATbigfoot.com>]

In article <216db6fd.0310082253.1f4e134b@posting.google.com>, Tom Gates
<tgates@isd.net> wrote:

> Before trying to resolder motherboard connections, have you ruled out
> bad AC power from the wall?  My GS would crash 3 or 4 times a day.
> Part of problem was large window air conditioner that kicked in and
> out and caused AC problems.  Problem is there isn't a real easy way
> for the average Joe to check line noise or voltage range and just any
> old battery backup doesn't do the trick.  I had to go (at the time)
> with an APC SmartUPS unit.
> 
> The GS runs off output from the battery in the backup unit. The AC
> side simply regarges the battery on a constant basis.  Regular backup,
> you are running on regular house AC, but is at least running through a
> surge protector. So this type of unit does not filter the AC - other
> than cutting off surge spikes and taking over when voltage goes too
> low.
> 
> Areas that have been affected by recent storm damage to the electric
> system are vulnerable to flakey AC power for some time afterward.
> 
> After UPS was added, the GS was restarted from a crash only twice in
> the next 2 years. Other restarts were my doing and were few and far
> between. Has now been running about 8 years without being turned off -
> except for one 2-week vacation.

Hi Tom, thanks for the reply.

Of course, without an oscilloscope or other measuring equipment, I
cannot completely rule out that possibility.  I did think of line noise
though.  Not specifically AC line noise, but the power supply's ability
to properly filter AC input and regulate the output voltage to the
IIgs.  I'm already using a third-party 120W internal power supply
originally intended for a 80386 PC workstation.  I replaced all the
electrolytic capacitors in that supply, and also tried swapping back in
the original Apple 60W power supply.  As if that weren't enough, I also
went ahead and replaced the electrolytic line filter capacitors on the
IIgs motherboard, just to be sure, since I knew they were old and had
been exposed to heat.  Then I also fattened power supply leads and
added thick jumpers to power traces on the GS motherboard, to further
lessen the likelihood of logic glitches due to regulation problems. 
The crashes didn't even lessen after all of that.  Also, I'm running a
Power Macintosh 6400/200 w/ G3 upgrade and an AMD Athlon XP 2100+
system on the same set of power outlets and have never had stability
problems with them.  Mac OS 9.1 even runs for at least a week of heavy
use without needing a restart.  So, with that knowledge, I've decided
not to concentrate on line noise as a likely problem.  If I had a UPS
to test with, I would.  I'm about out of ideas at this point, except
for assuming some bizarre logic failure on the motherboard is afoot.  I
hope someone can prove me wrong, but even if not, a new m/b shouldn't
be too hard to find.

1 restart a year is pretty remarkable, BTW.  Is your GS running a
server of some sort, or do you just find it convenient to leave on
24/7?

Thanks,
TK

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