Re: IIe hardware problem

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <3he3vf$62s0@blue.weeg.uiowa.edu>,
Steven Nelson <snelson@blue.weeg.uiowa.edu> wrote:
> 
> Can anyone offer some diagnostic insight?
> 
> After 10 years of faithful, continual service (ie, I rarely power down),
> my IIe enhanced (upgrade) suddenly got very sick.  It will crash at
> unpredictable times of a few seconds to several hours between crashes.
> Self-test will be either System OK, or RAM  0 0 0 1 1 0 1 0 .  Except,
> the RAM bits will never be same,  one time RAM  0 1 1 1 1 1 1 1, and
> maybe RAM  1 0 0 1 0 1 1 0 the next time.  No pattern of 0 and 1 I can
> discern.

It isn't likely that the RAM is faulty - it must be something else
causing RAM accesses to fail at random.

I would suggest removing ALL peripheral cards, the accelerator, etc.
(you should be able to leave the No Slot Clock there) and running the
self test again.  If that fails, it could be a fault in the MMU or IOU
logic chip.

If it passes, try again with just the ZIP installed.  If that fails,
it is probably a faulty accelerator.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand