Boox Tab Mini C severe ghosting ==> Faulty TCON-B controller?

[Anghirrim]

Hi,

I bought a second hand Tab Mini C some months ago, and it recently started showing some extremely severe ghosting, to the point that it's almost unusable for the black and white part.

Weirdly.... scrolling a manga is still OK (seems like scrolling kind of force refresh).

What I have really looks like all the comments on Reddit, with people complaining about the Tcon-B screen type (which... I unfortunately have, when looking into settings ==> About my device ==> epd).

See below for example: https://www.reddit.com/r/Onyx_Boox/c...ng_tab_mini_c/

Or this ==> https://www.reddit.com/r/eink/commen...?show=original

After some research, I can't seem to be able to find a fix. Did anyone face such issue, and if yes, did you manage to fix it?

Based on what I have read, watching videos could stress the tcon to the point that it finally fails working. I wouldn't be surprised that it's something like this, because it started appearing after a few weeks of intense manga reading/scrolling sessions with constant refresh.

Thanks,

[Renate]

It would be interesting to find out what the exact problem is.
Reports of people watching videos seems to suggest the problem is overheating and loss of connections.
I have not seen a display and I don't know if is using regular BGA connections.

If somebody is completely desperate, has a fairly unusable device and Onyx won't help you might try to reflow the connections with heat.
Even if you get a temporary and small improvement but it's definitely there it will prove what's up.
But don't even attempt unless it's already a lost cause.

[Anghirrim]

Thanks Renate,

For now, only static images are horrible.

I tried scrolling a manga yesterday and it kinda helps force refreshing the screen as long as you have something "dynamically" moving.

It's like, as if normal screen refresh (flashing) does not really refreshes the screen, but content scrolling does.

I'll try to take some pictures or videos.

Once it becomes completely unusable I'll definitely start playing around with your idea. I used to do it once on an old Xbox that had the red ring of death. My brother in law thought it was completely dead, so I borrowed him to have some fun. And reflowing the motherboard GPU with a heatgun was successful.

[Anghirrim]

By the way, I've been trying a few things on it yesterday with the hope of downgrading it to a previous version (currently on 4.2, planning to flash 3.5.4).

I got the firmware files and decrypted them (3.5.4, 4.0, 4.0.2 and 4.2).

Also entered EDL mode and made a complete backup (with .\edl.exe /u0 /r / backup0.img, from 0 to 5 for each LUN).

But now, the stock recovery does not have the adb sideload option.

Is there any interest in downgrading and see the effect on the ghosting or is it most probably hardware related?

Thanks

[Anghirrim]

A nice picture I took yesterday...

[Renate]

I wouldn't expect anything unexpected, but have you tried a screen grab?
If you have adb enabled you can try my adbgrab.exe

C:\>adbgrab.exe /s0.5

Undoubtedly it will show cleanly.

[Anghirrim]

Originally Posted by Renate

I wouldn't expect anything unexpected, but have you tried a screen grab?
If you have adb enabled you can try my adbgrab.exe

C:\>adbgrab.exe /s0.5

Undoubtedly it will show cleanly.

Yep, confirmed, adbgrab shows a clean screen.

Conclusion, it's hardware related and there is no "soft" fix?

[Renate]

Originally Posted by Anghirrim

Conclusion, it's hardware related and there is no "soft" fix?

Probably.

I would say from the whole history of this that it is a hardware problem.
The whole eink driver is so opaque and I've never had a color display.
I have done my own drawing using frame buffers and ioctls, but only B/W.

[Anghirrim]

Hmmm, I'll wait for it to become completely unusable and open it to see...

Thanks for the support, as usual!

[Anghirrim]

Well well well. Time has come for some opening.

Based on my son's feedback, he was reading a manga (scrolling was still ok) when all of a sudden, the screen completely broke.

He assures me that there was no shock (30% to 0% trust level on my side , but I cannot see any impact on the screen), and the rest of the story makes me think that he at least genuinely thinks he did not do anything wrong.

Even though, it really looks like a broken display... So reflowing might not help.

We'll see!

[Anghirrim]

Wow, I have opened many electronic devices, but this one is particularly strong, the clips on the corners maintain really really well everything in place!!

But we're in!!

[Anghirrim]

Originally Posted by Renate

It would be interesting to find out what the exact problem is.
Reports of people watching videos seems to suggest the problem is overheating and loss of connections.
I have not seen a display and I don't know if is using regular BGA connections.

If somebody is completely desperate, has a fairly unusable device and Onyx won't help you might try to reflow the connections with heat.
Even if you get a temporary and small improvement but it's definitely there it will prove what's up.
But don't even attempt unless it's already a lost cause.

Hi Renate,

I have opened it and took some closeup pictures of the mobo and screen connectors. Do you see anything that would be worth reflowing?

Thanks!

[Anghirrim]

Two more pictures.

[Renate]

Thanks, nice photos.
The photo with the thumb on the small flex is the capacitive touch sensor.
They always have the tiny processor mounted on the flex.

The actual "T-Con" is embedded in the screen.
The photo of that is from a shard of a truly broken B&W screen.

The other photo is your device showing what the chips are doing.

Sorry, I really think that your device has a cracked screen now.
Does any part of it behave normally? Or at least changing sometimes?

[Anghirrim]

Nice! Thanks for the explanations and picture with the addition of what the different modules do.

I also think it's now a lost cause. It now really looks like my good old Cybook Opus when it met with my butt one day.... To answer your last question, nope, none of the parts even refresh anymore. There is a tiny flickering effect on one of the very thin lines, which actually stops when reaching the "border" between two different areas.

The screen has always been protected by a rigid case, the official Onyx one, it apparently hasn't been enough, or maybe something was caught between the screen and the cover...

So now two options, either something really happened by mistake, or either my son is a professional liar.

Just thought I would ask and at least share the pictures of the mobo, as it might be useful for some other people.

Time to wait for the Kaleido 4 then...


Note: I have checked quickly on Internet, but there is no available replacement screen for this reader...