On Sun, 22 Apr 2007, Joel Kolstad wrote:

"Franc Zabkar" wrote in message
...
I recently went shopping for a washing machine. I only saw one that
didn't have a microcontroller. As an engineer I can appreciate the
gadgetry, but as a tech I also understand the repair cost.

In theory the electronic ones should be more reliable... the traditional
washing machine timer, with a bazillion little detents pressing spring-leaf
switches *will* fail, it's just a question of when.

Pretty much guaranteed that *every* washing machine will fail, given
enough time, electronically-controlled or not, the prime cause of failure
being vibration in the spin cycle inducing strain in the mechanical
components, but electronic circuit boards are as susceptible, if not more
so, to mechanical strain.

Personally, having kept our vintage (100% mechanical) washing machine
going FAR past it's reasonably-expected lifespan by maintenance
as-and-when, seems to me that the major causes of failure/stoppage are A)
Blockage of the outlet impeller by items that slip between the inner and
outer drums, ie. coins from pockets, safety pins, items of jewelery, etc.,
and B) component fracture, ie. inner drum mounting brackets, rubber
glands, and/or fractures/disintegration in the concrete damping blocks.

The old cam-driven microswitch program controller has much to recommend
it; it stands up to vibration reasonably well, is cheap, and the only
thing that is likely to disrupt its program is contact failure (which is
easily dealt with by a can of servisol/WD40) or, at an extreme,
dismantling and going over the contacts with a nailfile/emeryboard. Any
weak solder joint in the "electronic" equivalent, subject to the same
mechanical forces, can produce an "intermittent" failure mode that can be
an absolute ******* to track down, and result in many hours of fruitless
investigation.

All-in-all, I'd side with the "appropriate-technology" camp. If it does
what you want it to do, with the minimum of fuss, then it's the right
product. The more "knobs-and-whistles" there are, the more there is to go
wrong. If it ain't broke, don't fix it.

Cheers,
Pete.