Re: Apple IIe dead?

["Paul Grammens" <grammens@svn.net>]

Sabino Maggi <maggi@ien.it> wrote
>
> What I don't understand is the fact that pulling out the chips and
> removing oxide and dirt from the sockets and pins could work. You surely
> have much more experience than me with Apples and this is probably
> typical of old Apples, but it seems so strange to me...
> Really it seems a very strange, cross-your-fingers-and-try fix, as
> Rubywand says... (By the way, what does "BS try" mean?)
>
> I would surely expect this to be necessary in an old machine, which has
> rested for years without being turned on. Then oxide and dirt prevents
> good electrical contacts and you need to clean everything, but my Apple
> II had been used for a couple of days, without any problem.
> I use all sorts of electronic instrumentation, also very old stuff, and
> I have never experienced such a thing.
>

What can happen is that the IIc warms up and some parts expand slightly. One
of the hundreds of socket pins moves very slightly and breaks it's last
electrical connection. Some crud or oxide is now preventing metal-to-metal
contact. You type some command and the IIc trys to use a part of memory
affected by the defect and it crashes. You reboot, but that pin is still not
making contact, and it crashes again. Etc. Everyting that once worked and
now doesn't stopped working at some point in between, you just happened to
observe it within a few minutes of when it happened.

Another weak link is the electrolytic capacitors. They go bad over time,
usually creating an open, sometimes leaking and corroding the surrounding
components. This is very common in Macs, those damn silver dome-type surface
mount electrolytics are only good for 5 years or so. So take a look at them,
too. Unfortunately, you need and ESR (effective series resistance) meter to
measure them.
-Paul