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How a Leather Cover Crashes the Kindle 280

An anonymous reader writes "Amazon has started offering refunds to Kindle owners who own the unlit leather case who claim that it causes their Kindles to reboot, but are playing dumb on the cause: "our engineering team is looking into this." People have been wondering how a leather cover could possibly crash an electronic device, and why is Amazon offering money back if they don't think there's a problem? It seems that some of the folks over at Connectify have figured it out, and it's a doozy!"
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How a Leather Cover Crashes the Kindle

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  • Re:Yikes! (Score:3, Informative)

    by yincrash ( 854885 ) on Tuesday December 21, 2010 @03:56PM (#34632908)
    It looks like a flaw on the part of the cover maker. Amazon could put some amperage limiting circuitry, but I imagine it would raise the cost.
  • by specialperson ( 1963158 ) on Tuesday December 21, 2010 @04:04PM (#34633034)
    First, his meter's reading 2 Megaohms, not 2 Ohms. I guess he's not much of an "Electronics Person". Second, it would appear that he's measuring conductivity though his body to achieve that number. Both of his fingers are touching the probe tips.
  • 2 Ohm or 2 Megaohm? (Score:5, Informative)

    by Danh ( 79528 ) on Tuesday December 21, 2010 @04:06PM (#34633062) Homepage

    The linked article at Connectify says they measured a resistance of 2 Ohm, but on the picture I read 2 MOhm!

    Check yourself with the large version of the picture.

  • by jeffmeden ( 135043 ) on Tuesday December 21, 2010 @04:10PM (#34633124) Homepage Journal

    First, his meter's reading 2 Megaohms, not 2 Ohms. I guess he's not much of an "Electronics Person".

    Second, it would appear that he's measuring conductivity though his body to achieve that number. Both of his fingers are touching the probe tips.

    That was the first thing I thought of when seeing the picture as well... Thank goodness he posted the full res version of that so we can very clearly see the M on the meter. What a maroon.

  • by Khyber ( 864651 ) <techkitsune@gmail.com> on Tuesday December 21, 2010 @04:28PM (#34633420) Homepage Journal

    It's the hooks. I just took my fiance's mother's Kindle and pulled her non-lit leather cover off.

    Paint worn to SHIT, metal exposed. Metal is brass.

    I didn't even use a multimeter, I just used some new equipment from Nichia's yesterday visit to see if it would actually work as a full conductor.

    Lit the LED up without any problem.

    Quite conductive.

  • Re:Yikes! (Score:4, Informative)

    by Mr. Freeman ( 933986 ) on Tuesday December 21, 2010 @04:31PM (#34633466)
    That's actually a terrible idea. Limiting the current through the hooks would still result in lots power being wasted, just not enough to crash the device. Over time this will cause the battery to discharge completely, which results in the owner charging it, which leads to greatly reduced battery lifetime.

    If you run your batteries between 20% and 80% charge, you get orders of magnitude more life out of them compared to running them between 10% and 95% charge.
  • by mrjatsun ( 543322 ) on Tuesday December 21, 2010 @04:32PM (#34633492)

    My son's Kindle has this problem... I removed the cover the other day and it has not had it sense. I just broke
    out the multimeter, I was unable to get an electrical path even when scraping the paint on the hooks.

  • Re:Yikes! (Score:5, Informative)

    by jgagnon ( 1663075 ) on Tuesday December 21, 2010 @04:47PM (#34633734)

    Breakdown: The lighted case gets its power from the connectors that hold the Kindle in the case. The unlit case has these two connectors physically connected even though there is no light. Putting the Kindle into the unlit case where the metal contacts are clean causes a short between the two connectors.

    The ability to get power through those connector points was by design in the Kindle or the lighted case never would have been able to be designed the way it was.

    It sounds to me like the engineer(s) involved with the unlit case did not communicate well with the Kindle engineers or vise versa.

  • by scdeimos ( 632778 ) on Tuesday December 21, 2010 @08:20PM (#34636206)

    As already mentioned above, the multimeter in the picture is reading 2.164 megaohms which is quite a high resistance and would make no difference at all to the operation of the Kindle.

    It seems that the blog owner has realised their mistake and replaced their blog entry with the content of another, but not before it made it's way into Google Cache [googleusercontent.com]

    For those interesting in seeing the high-resolution "Oopsie" image, it is here [blogspot.com].

  • by Monkeedude1212 ( 1560403 ) on Tuesday December 21, 2010 @08:35PM (#34636336) Journal

    Some things are best left to Google ("What's the capital of Assyria" etc), but turning that into "anything should just be Googled" is pretty counter-productive.

    I've never disagreed with a sentiment so much before online. The internet is an incredibly vast wealth of knowledge and I feel that any time you have any question, it should be used accordingly.

    It's amazing how much information you have access to, it is not difficult to self teach yourself computer programming, car mechanics, advanced physics, art techniques, or almost anything else using just internet information sources, and supplies at home to get you started. Obviously if you want to do car repair you should have a car and the tools necessary for the job, but understanding what to do and whats needed can easily be found online, with step by step guides!

    The simple question "How does one do something" is the BEST kind of question the internet handles. There is even a popular site dedicated to it, howto.com - and Youtube will have tons of videos on topics like that.

    The problem is that handy did not ask for backgruond information on where it comes from, he did not ask how to acquire those materials in prison, he did not ask about smuggling or manufacturing equipment - he merely asked how to light a cigarette with batteries. The video addresses that.

    If, perhaps, he's interested on how to Smuggle items into prison - he should google "How to smuggle items into prison" and he can see the news reports on how people have tried to smuggle things in before.

  • Am I going blind? (Score:3, Informative)

    by McPierce ( 259936 ) on Tuesday December 21, 2010 @09:21PM (#34636704) Homepage

    I'm on the Connectify blog and I don't see anything about leather cases or flaws. When I search the page for "leather" I only see the tag and nothing else.

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