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Motherboard sudden death in 1-week old phones?

  1. Oct 31, 2018 #1
    What accounts for sudden death failures in 1-week old smartphones, given mass production? If one fails, surely the rest should follow suit, assuming user usage is fairly equal?

    And what accounts for those in which the motherboard died after 1 year? This indicates proper implementation given that it didn't fail within a week, yet it still died prematurely.
     
  2. jcsd
  3. Oct 31, 2018 #2
    bathtub curve

    This a kind of expected. Sometimes there is some addressable problem behind it, sometimes there isn't.
     
  4. Oct 31, 2018 #3

    CWatters

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    Not so many years ago at least one manufacturer of set top boxes suffered significant number of failures because they appeared not to understand how heat effects the life expectancy of electrolytic capacitors. That halves for every 10C increase in temperature and they don't all start off with a very long life expectancy. Get it wrong and you can get lots of failures within warranty.
     
  5. Oct 31, 2018 #4
    That's why I wrote assuming usage is identical - why do some fail prematurely under heavy load while others do not? This is in regards to the exact same motherboard in the same models. Sometimes a press release states that it only affected a small amount of those models - why those in particular and not all of them?
     
    Last edited: Oct 31, 2018
  6. Oct 31, 2018 #5
    Take one of those explanations - installation error. This surely can't be applicable to massproductions of a given product, unless you have a concentrated group in a specific manufactering building that for some reason are incompetent.. Could it be due to coincidental, environmental conditions (tropic summer?). Aren't those conditions controlled for in advance (proper cooling in the building)?
     
  7. Oct 31, 2018 #6

    CWatters

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    Electronic devices have many failure mechanisms and causes. See...

    https://en.m.wikipedia.org/wiki/Failure_of_electronic_components

    Most manufacturers build in batches using components from multiple vendors whenever possible. They usually keep traceability records so they know who supplied the parts for each batch or range of serial numbers. Batches of components that turn out to be failure prone might only have been used on one batch of end products, a number of batches, one product or a whole family of products. Good manufacturers analyse their warranty returns looking for common failure modes so they can identify problem early and improve the quality and reliability of their products.
     
  8. Nov 1, 2018 #7
    I did not know that. Doesn't really make sense to me from a business standpoint. How would you evaluate a given models quality if it's internal parts are not the same depending on where it was manufacturered? The hole point of models is uniformity. My IPhone X is supposed to be the same as the IPhone X you got, I think...
     
  9. Nov 1, 2018 #8

    CWatters

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    If you use parts that are only available from one supplier what happens when that supplier can't deliver for some reason? What happens to the price of an item if your supplier knows you cant buy it from anywhere else?

    In some cases (eg semiconductors) you can't avoid being single sourced but for those you have to write good contracts. One of the advantages claimed for the ARM processor is that many foundries have licenses to produce ARM based designs. Ok so you might not be able to buy exactly the same part from multiple sources but at the outset you may have a choice who makes your custom IC and that gives you more negotiating power before you sign the contract.

    Some companies prefer to be vertically integrated to avoid supply problems. For example Tesla identified that global battery supply was going to be an issue so they set up their own plant in a joint venture with Panasonic.
     
  10. Nov 1, 2018 #9

    256bits

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    Of course it makes business sense to evaluate failure rates, and in turn reliability of the product sent to the general market.
    One wants a product that performs its duty in most cases.
    One does not want a sloppy product, as sales will drop due to underperformance.
    But one does not want to make a product that is overly engineered, as that adds to the product cost and sales drop due to it becoming overly expensive.
    Its a sort of a balance of production costs, warranty costs from failure returns, to end of life of the product, so that a business does not put itself "out of business" from not paying attention of how well, or not how well, its product is performing.

    Except for products that are expected to have to perform all the time, such as for military, health industry, aerospace, or for other safety reasons ( bridges, buildings for example ), in which case the infant mortality is weeded out by redundancy or by other ways.

    The manufacturing process for the final product is a long chain of events from obtaining the raw materials and purification, to manufacture of small parts from the raw materials, design of a working product, and assembly of the final product.

    Design can have weak points, such as the capacitors mentioned above.
    Raw material purity can vary - if 97 % pure copper ingot is required and your supplier provides 97.5% you may be ahead of the game, but if your pulling copper wire, how do you actually know that each meter is 97.5% and not 97.9% in some places and 96.8% in others.
    Manufacturing and assembly has tolerances for the small parts as well as for the final product.

    Everything is a " law of averages", statistical sampling, with a good deal of hope, and mathematical ensurance that a minimum of product, a value assigned by you, do not turn out to be lemons.

    this might be a good read.
    http://www.gatewaycoalition.org/files/Enggstats/htmls/Ch4.pdf
     
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