On Fri, 3 Feb 2017 10:12:56 -0500, Phil Hobbs
wrote:
On 02/02/2017 09:36 PM, Jeff Liebermann wrote:
Todays products are intentionally designed to be difficult to repair
and to only last as long as the warranty period. With the proper
design tools and models, it is possible to predict the life of an
electronic (or mechanical) product. Anything that lasts longer than
the warranty period is deemed to be "over-designed". It is then
redesigned using lower rating or cost components so that everything
blows up at the same time. I've seen it happen.
Oliver Wendell Holmes wrote a very funny poem about that, "The Deacon's
Masterpiece, Or, The Wonderful One-Hoss Shay".
Here it is, read by Eddie Albert.
https://www.youtube.com/watch?v=wiOHhhwnK6k
Cheers
Phil Hobbs
Thanks, that was good and quite appropriate.
While attending college, I lived for a time in a large old house aptly
named "the fire trap". I could hear termites chewing away in the
walls. About 3 years after graduating, I returned to visit the
school, and drove by house. It looked much the same as when I lived
there. The next day, on my way out of town, I drove by again and
found that the house had collapsed in a heap. No wall was left
standing. According to the news, it had fallen down by itself and
without warning, injuring a few students in the process. It's much
like the medieval cathedrals, bridges, and other structures, where the
failure of one tiny arch, will cause the entire structure to collapse.
In a previous life, I tried to design a "warranty timer" into a
product. Actually, it was suppose to accumulate and display the
amount of time that the unit had been powered on to help establish
maintenance intervals. In previous products, a mechanical
counter-timer was used, but for this version, it was deemed too big
and expensive.
http://www.alliedelec.com/images/products/Small/70132720.jpg
I found a company that made an electrochemical equivalent. It was
housed in a glass cylinder, similar to a common 3AG glass fuse. Inside
was some chemical solution. When a few volts of DC was applied,
electrolytic action caused one end to slowly turn dark, thus
indicating the amount of time that the DC was applied. Sorry, but I
couldn't find the vendor or an equivalent online. When the required
maintenance was performed, the indicator would be replaced as it could
not be reset.
During the design phase, I liked to joke about installing a 2nd timer
in the product, which would blow it up after a specified operating
life. I even designed a place for it on one of PCB's. I stopped
joking after I found that management was taking me seriously and
discussing such things was how to handle extended warranties. The
device was later removed in a cost reduction exercise, but the
component outline remained in the printed manual, resulting in
numerous embarrassing questions because someone had labeled the part
as a "warranty timer".
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558