Interesting Switch Autopsy

We put a lot of trust into some amazingly cheap components, sometimes that trust is very undeserved. Long gone are the days when every electronic component was a beautifully constructed precision lab instrument.  As [Rupert Hirst] shows, this can be a hard lesson to learn for even the biggest companies.

[Rupert]’s Nexus 5 was suffering from a well known reboot issue. He traced it to the phone’s power switch. It was always shorting to ground, even though it clicked like it was supposed to.

He desoldered the switch and pried the delicate sheet metal casing apart. Inside were four components. A soft membrane with a hard nub on the bottom, presumably engineered to give the switch that quality feeling. Next were two metal buckles that produced the click and made contact with the circuit board, which is the final component.

He noticed something odd and  busted out his USB microscope. The company had placed a blob of solder on the bottom buckle. We think this is because steel on copper contact would lead to premature failure of the substrate, especially with the high impact involved during each switching event.

The fault lay in the imprecise placement of the solder blob. If it had been perfectly in the middle, and likely many phones that never showed the issue had it there, the issue would have never shown up. Since it was off-center, the impact of each switching event slowly deposited thin layers of solder onto the copper and fiberglass. Finally it built up enough to completely short the switch.

Interestingly, this exact problem shows up across different phone manufacturers, somewhere there’s a switch company with a killer sales team out there.

40 thoughts on “Interesting Switch Autopsy

  1. Once consumer products was built with way too expensive industrial grade components, that made a houshold radio cost a few months salary.

    Now consumer products (and some industrial) are made dirt cheap by dirt cheap components.that doesnt last, but on the other hand, how many radios could you buy for a months salary?

    Somwhere there must have been a sweetspot, would that have been in the 70’s ?

    I have a few radios from different eras, and the stuff from the 70’s (not the Asian stuff) seems to balance quite right on the sweetspot of price/quality.

    What is the opinion among others?

    (of course there might have been other times on other products)

        1. There’s this old chestnut… http://jokes.edigg.com/Computer/Quality_Control.shtml

          Now it used to be, that Japan was the underdog cheap manufacturing nation, in the 50s into the 60s, made in Japan meant about the same as made in China does now, in the 70s, they picked up their game, in the 80s, they really began to pwn, and in the 90s they began finally to penetrate the consumer consciousness as a quality producer…. now later in the 90s they realized how well regarded they had become and began to take higher profits.

          1. The difference is that Japan worked to improve quality and build a reputation for producing good quality products. My impression is that either China really doesn’t care or has never figured out the quality angle. They just want to be the low-cost provider.

          2. When they’re making stuff for someone else, they either fall right in line with the customers desire not to leave a penny unpinched, or don’t care too much. But Chinese firms that are innovators and manufacture their own products can produce good quality products. Huawei would be an example. However, many apparent Chinese brands, are not innovators, and are making copies of someone elses product, even copies of copies, and are likely not of good quality. You get the one odd weird thing where there was a Chinese original, and the copies turned out better, there was a dash cam like that. Anyway, hunting for something on AliBaba etc, it’s all a bit of a crapshoot and gordian knot, trying to tell whose design a certain piece of tech was originally, and who are one of the dozen or more copiers.

    1. IMO there was a tipping point around 2005, before that you could still find stuff not made in China. There was another inflection point mid 90s where Japanese goods weren’t sold cheap any more. Contrairily though, cars were terrible mid 90s to then, then started to improve.

      1. You and everyone else posting their version of “Modern quality is crap” has not studied much Manufacturing history. There has always been a push to reduce cost and Management & Engineers have always pushed too far. The Model T Ford was a major notable automobile cost reduction, so were the Liberty Ships built during WW2.

        And regarding today’s technology? The modern smart phone you are likely using to read this posting is a great example of modern high quality electronics that was likely made in China. Our problem is we (Americans) are quick to assimilate product quality then we are just as quick to bash minor quality glitches, and sometimes major issues, without appreciating where we are at today.

        And the basis of my opinion?

        One of my hobby’s happens to be a vacuum tube radios and I’ve worked on radios built from the 1920’s through the 1960’s. This means I also have an interesting cross section of how manufacturing practices evolved over a 40 year span. I’ve also been involved in “modern electronics” from the 1960’s through today, so you might as well expand that exposure another 50 years! I could point out cost cutting efforts taken by the radio industry for each century – from the1920’s through today. Some worked out, some not so much.

        And no, I’m not THAT old – I’m 57 and I got really serious in electronics when I was 14 years old.

        1. Well, the product still has to function the warranty time, and not to many can be dead on arrival, but other then that, cheapest possible.

          On the other hand, some companys want to have a solid quality reputation, and that would have been the same sweetspot.

          1. That’s when they shorten warranties, stores shorten return policies, and your broken crap will only be repaired if you ship it insured by courier to a central depot…. Meaning you don’t bother if it was worth less than $100…. Only costco seems to honor warranty in store any more.

        2. Cheap China? How about Cheap Americans? And no, I’m not Chinese. China is more than happy to build any quality we (Americans) are willing to pay for. You can blame the quality of every cheap product you’ve bought on market pressures driving down cost.

          1. Not entirely true, there are cultural aspects at play as well. Read Paul Midler’s “Poorly made in China” for a good insight into this. It’s not always the buying deciding how crappily his product gets made!

  2. I am working for a company that makes (quite successfully) simple, long-lasting household goods. No rocket science, but we got an innovation award every now and then and had a loyal consumer base and some well-established brands. Along came an “investor” and bought a majority of our shares… you know, one of those companies that invented the concept of “leveraged buyout transactions”. Even though healthy and profitable before, we now had to generate an additional two-digit percentage in profit to finance the greed of our new overlords … that was the tipping point when the quality of our products was compromised to an extend that even our most loyal consumers began looking for alternatives to our offerings.

    Surprisingly, there was no big campaign to win back our customers – instead we got presentations on how to “innovate smarter”: It’s simple: you go to China, find an ok-ish product, slap your brand on it and VOILA: THAT’S how you innovate!

    … to cut a long story short: the tipping point is not defined by a certain percentage or a price point but by a certain mind-set: from how can we WOW the consumer to: HOW CAN WE RIP CONSUMERS OFF without them noticing immediately?

    1. The tipping point was when USA move from industrial manufacturing to financial engineering. It used to be a competition of product quality between the west and the east.

      Now people when buying just sort it by lowest price with a familiar brand and buy it. Sometimes old people get stumped when they bought a known brand and it didn’t last as they expected it based on old purchase so they just buy the cheapest one since it will break anyways.

    1. There’s occasions where “refurbished” means they checked it powered on, blew the dust out, wiped it down and repacked it…. then there’s occasions where consumer returns with a common problem were actually remanufactured, if there were enough of them to make it worthwhile, by correcting the fault, then blown out wiped down and repacked. However if something came in with an intermittent glitchy button and a crack across the top corner of the screen, you can rightly wonder if it got a new screen, happened to be behaving while tested briefly, and then got shipped out with a failing button.

    2. I do – I’ve work for this type of business. 80% or more of refurbished products are tested, cleaned and returned to service. In most cases the refurbished product was not electrically defective. There may have been a cosmetic issue that caused the return, But more than likely there was nothing wrong with the product at all.

      The other thing to understand is the refurbish process can’t make the product better than new. So, for example if a particular cellphone model tends to get hot or drop calls then the refurbished cellphone will tend to get hot or drop calls. The refurbish process doesn’t re-engineer or ‘fix’ design issues, they legally can’t even if they technically could, a cellphone is a FCC regulated transmitter. The same would be true for crappy switches. If a cell phone came in for something other than a crappy switch that was not failing yet, the process would fix what was failing (or nothing at all) and the cell phone would ship back out with a crappy switch. This is because there is no way for the refurbisher to know if the switches are crappy and there is no cost effective way to test the switch for “crappyness”.

      One exception would be if the cellphone company identified an issue with the switches. In that case they would negotiate a price for replacing all of the switches as the cell phones were processed through the shop. But my personal experience is this never works well and it’s better to leave the existing switches installed. This is because in most cases what was going to fail has already failed in the field and replacing all switches with new just introduces a fresh lot waiting to fail!

  3. I had the exactly issue, which I didn’t doucmented since that sounds so normal that wasn’t worth to write about. I did not expect that wasn’t so common to know about this weakness of modern consumers design. Those buttons are rated for a ridiculous number of pushes. It is not designed to last – in consumer electronic devices.

    What if I told that the digitizer (touch sensor of the phone) is rated for (only?) 300K tapping? :)

        1. This is only true for a resistive tough screen. A capacitive touch screens works by creating a field on the opposite side of the glass you are touching then the location of that field is measured. Modern smart phone touch screens are capacitive.

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