

Why the Leather Cover Crashes the Kindle 3 - Bud
http://connectify.blogspot.com/2010/12/why-leather-cover-crashes-kindle-3.html

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jdminhbg
The post has changed for some weird reason since submission. Here's the text,
via the Google cache:

I love my Kindle 3. I was in the middle of writing a blog post about how great
the Kindle 3 and Connectify work together (which I will post in the next day
or two), but started having a problem with my Kindle crashing randomly. I
searched the forums and lots of people reported the same problem, but only
when they had the Amazon leather cover without a light. But no one ever saw
this happen on the version with the light, and no one seemed to explain how
that could happen.

It didn't seem to make a lot of sense that a leather cover would crash an
electronic device, so I got curious and started to look closely at my Kindle's
case.

The unlit leather Kindle case has 2 black hooks that slide into the side of
the device to hold it into place.

So then I looked at the lighted version to see how it's different:

On the lighted version, the hooks are gold! That's how the light gets power,
of course. One of them is power and one of them is ground.

So then I looked really closely at hooks on my cover:

It's coated in a black, textured paint, which does not conduct electricty. But
look closely along the edge, where it rubs against the inside of the Kindle.
It's still black, but there are now spots with a smooth texture where the
paint has rubbed off.

So out came the handy-dandy Radio Shack multimeter, set to measure resistance.
I found a smooth point on each of the hooks and:

They're connected? It's hard to get a good reading, without scraping all the
paint away. But that's a connection... remember that's how it powers the
light. Depending on your contact you can see some pretty low values, which
imply a pretty good connection between the two.

This is why the Kindle crashes. Once a bit of paint has rubbed off the hooks,
power starts flowing through the cover, leading to brownouts; the CPU does not
get enough juice to operate properly and ends out either hung or rebooting!

~~~
devindotcom
Escapist has the pictures.
[http://www.escapistmagazine.com/news/view/106355-Amateur-
Eng...](http://www.escapistmagazine.com/news/view/106355-Amateur-Engineer-
Figures-Out-Why-His-Kindle-Randomly-Restarts)

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ghshephard
Should be simple to get more data - just short out (with appropriate
resistors!) the connection points and see if your Kindle Crashes.

50%+ of my reading get's done by the K3 nightlight - I'm surprised people
manage to get by without it.

~~~
ovi256
But that's the point: to trigger the brownout that crashes the system, you
need to really short-circuit those points. So resistors in series won't do it.

~~~
nitrogen
You use the resistors for safety to determine how much current is needed to
kill the device. I'd use a potentiometer, and turn down the resistance until
bad things happened. Or, more likely, I'd insulate the hooks on my case or
sever the connection between them, and not risk damaging the Kindle.

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olalonde
This post has nothing to do with a leather cover crashing the Kindle (apart
from the tags and the URL). Are people up voting this before having read the
actual article or am I missing something?

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staktrace
I believe the website changed the content of the article. Note how his blog
has two posts with the same text now. Probably trying to take advantage of all
the Slashdot/other traffic to sell whatever.

~~~
barrkel
I think he may have taken in the criticism over the 2MΩ reading and started to
think he made a mistake.

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davidw
Interesting... I had some random crashes with mine, and I have a leather
cover. Haven't had any lately. The worst was when our plane was supposed to
leave from Amsterdam for PDX, and I thought I was going to be stuck for the
whole flight with no Kindle... it wasn't reacting. Luckily it rebooted or
something, but I was getting pretty pissed off.

~~~
ardit33
If the device is really acting up, and needs restarting teep the power
button/slider 'on' for 12-15 seconds. That will force a reboot on the device.

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gimpf
Ähm... has the page changed? There is not a single mention of a Kindle crash,
and the DDG summary of the page when searching for the title shows something
completely different than what I see there. Hm.

~~~
Bud
Looks like the blog did indeed "update" the page at the same URL, after I had
posted the link here.

I apologize for the confusion, even though it's the blog's fault. :)

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jrockway
Wow, I had no idea you could get power from the hook ports on the Kindle. I
have a separate light that uses batteries.

I may have to do some hardware hacking in the near future!

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ndunn2
So weird, my Kindle 3 crashed twice yesterday, something that's not happened
in the 3~ months I've owned it. And I have a leather cover. Curious if this is
why.

