Kindle Paperwhite problem

[Gammyleggs]

Hello all

I have a Kindle paperwhite with a problem that I hope the techies amongst us can help me with.
It has a damaged screen, I have bought a "donor" demo kindle from a well known auction site and following the advice on this forum and you tube have swopped over my mobo to the replacement screen, so far so good.
However when I refit the battery the kindle tries to boot but after a number of attempts it shows a screen saying "your kindle needs repair" contact amazon customer care....
If I re fit the mobo back to the original damaged screen it works perfectly, am I right in thinking that amazon "locks" the mobo to the screen??
Has anyone else come across this before?
Does anybody have a way to fix this?
I have trawled the forum for an answer but so far not found anything so here's my first post.
Any help will be gratefully appreciated!

[j.p.s]

Are you certain that that the "demo" kindle is exactly the same model as your damaged kernel?

What are the first 6 characters of each serial number?

[Gammyleggs]

Hello J.P.S

Thank you for your reply, The demo kindle has the settings option greyed out so I cannot get the serial number, (short of connecting a serial connection to the mobo and reading it off during the boot).
Of course if the demo kindle can be un"demo'ed" that will also do as a fix
The two screens look identical, and connect the same to the mobos.
I assumed it would be a simple swop job as I have swopped screens on my sons keyboard kindle and his kindle 4 in the past with no problems, its just my luck that my paperwhite is not playing ball!
My worst fear is that amazon have serial numbered the screens and locked the screen and mobo together in the software.

[j.p.s]

There have been a number of screen replacement threads over the years, but I can't seem to find any here or the Developer's Corner subforum, which is a better place to ask for details. Kindles have fewer hardware revisions than models, but even within a model, the waveform or other screen driving details might change.

[eddie.t.h]

What exactly the paperwhite model do you have? What's your error code? Paperwhite 2 and 3 look practically the same inside but have completely different screens and slightly different motherboards.

[Gammyleggs]

Hello all

Thanks for the replies.
The two Kindles are the same model numbers on the case;- DP75SDI
I am sure you are right about the screen waveforms as the screenshots I have attached with the mobo's swopped over in both of them shows how the image is way out of proportion to the actual size of the screen, one is way too big.
The other has the error code hidden because of the size of the image on the screen is way too small.
Looks like I am up against a brick wall with this, unless the memory chip on the screen ribbon can be read and re-programmed with the correct waveforms??.
Then will the touch screen be the same and need re-programming??

https://photos.app.goo.gl/o4nHJc4BwEJhLWFx8

[JSWolf]

@Gammyleggs can you please change your URL? There is no reason on MR to use a redirecting URL when there is a full URL you can use. MR does not have a limit on the size of the URL. I will not click on redirecting URLs.

[Gammyleggs]

Hello J S Wolf

I am very new to this forum and all forums come to that and do not understand how to "upload" pictures.
I tried to upload just the jpg images direct to the site but cannot find a way to do it only a box requesting a HTTP link, so I set up an account with Google pictures and shared the album.
Please explain what you mean "change your url"?
Sorry for being dense but its my age as my grandchildren would say.

[eddie.t.h]

You definitely mistook the Paperwhite 2 for 3. Both on the case have DP75SDI. That's why you have a disproportionate image. PW2 has a lower screen resolution.
You are not swapping these motherboards. The only thing left for you to do is do undemo.

[Gammyleggs]

Hello Eddie T H

Thanks for the info that makes perfect sense.
The other option is to undemo, I have read a number of articles about undemoing kindles but so far have not had any luck.
The easy method of opening a search bar and typing in ;demo does not do anything on the one I have, unless I am missing something.

Is there another easy way or is it down to re-flashing the software?

I have attached a serial adaptor to its mobo and tried to force it into diagnostics mode but it will not do that, the boot sequence just sails on past the press any key to enter diagnostics mode prompt no matter what I press.

I have managed to halt the boot sequence and exit to the uboot prompt right at the beginning of the boot sequence but again it refuses to respond to any typed input after that.

[eddie.t.h]

The only method I know is software installation and factory reset. You must have a working serial port. Maybe some connection problem?

[SKK]

Originally Posted by Gammyleggs

Hello Eddie T H

Thanks for the info that makes perfect sense.
The other option is to undemo, I have read a number of articles about undemoing kindles but so far have not had any luck.
The easy method of opening a search bar and typing in ;demo does not do anything on the one I have, unless I am missing something.
.

The steps in the below post worked for me.

https://www.mobileread.com/forums/sh...29&postcount=6