Teclast X98 Air 3G (C5J6) dead?

[highwind]

Hi everyone,

 

Perhaps someone could help me:

I ordered a Teclast X98 Air 3G (C5J6) for the girlfrind of one of my (non-geeky) friends about 10 weeks ago. The device arrived here about 4 weeks ago and I updated the Android ROM to the official 5.0 (and did some stuff as root, removed all the bloatware, changed launcher etc) and did a fresh install of Win 8.1 including all drivers. I tested both systems quite extensivly and everything was working fine. After that I handed the tablet to her and showed her some stuff the tablet was capable of. She used the tablet happily for about 2 weeks but then she told me it isnt working anymore, the screen doesnt light up no matter what she does and the battery doesnt get any warmer while being connected to the charger. I said I will look into it and got the tablet from ehr today and after some testing I cannot get the device to do anything either:

• neither power, nor power+vol-/+ (or + and – together) does anything
• different chargers and usb cables (all working for other devices I own) seem to load the tablet (neither the charger nor the tablets gets any warmer)
• connecting the device to my pc (which has all the drivers for the tablet installed) doesnt do anything, no hardware recognized, not even the common sound when you connect a usb-device under Windows

I opened up the tablet to look if I can see any obvious faults on the mainboard, but everything looks fine, all cables seem to be in the right place and there is no “carbonized” spots or obviously damaged capacitors

 

 

I assume either the mainboard just broke down or that there is a problem with the battery/usb port… Is there any advanced advice what I can do to see if the tablet is still able to do atleast something? I really like to avoid sending it back to China….

 

[TecKnight]

As long as you have it open, my first suggestion is:

1. Disconnect/desolder the battery from the motherboard.
2. Test and see if the battery is charged.
3. If it is not charged, charge it using a 5v source.
4. Reconnect to motherboard and try powering it up again. Note: Do this even if you found battery to be fully charged.
If that does not work, you can try flashing the BIOS externally

TTTTecKnight's Teclast Tutorials series

[highwind]

Thanks for your reply TecKnight

I got a multimeter from one of friends and the battery shows 3,94V which probably means it is fully charged.

As I am not very good at soldering (and don’t own such a small soldering tool) and don’t want to void the warranty soldering isn’t really and option – besides, the soldering points look just fine, I don’t think that this is the problem.

For flashing the BIOS externally I need a eeprom programmer, correct?

Is it possible to do any “low level communication” from the PC to the tablet? Like ADB commands or something like that?

[Martynas]

If BIOS is bircked no low level communication for you just reflash with eeprom programmer.

[highwind]

Mhhh, ok… Thing is, I dont own an eeprom programmer and I have my doubts that a bricked BIOS really is the problem (as the BIOS was not touched at all) so buying one would be an expense which probably will be wasted…

I think I dont have any other realistic option besides contacting geekbuying and send it back to them :/

Anyway, thanks for all your replies!

[Martynas]

Could you get more details, it happened after using which OS? Does it was on low battery? And etc?

[highwind]

She said the tablet was in Windows and battery was very low before she put it aside and fell asleep. The next morning the tablet was off (she assumed battery empty) and she plugged the charger in. Later that day she tried to boot the tablet but it didn’t react , charger and battery both were cold…

[Elias Mandouvalos]

I made a registration to the forum, only to say that this is exactly what happened to me. First day I’ve got the tablet in my hands and I’m checking the windows 8. I was so excited that I’ve drained the  power until 4%.So I power it off and, connect it to his plug overnight. Next day, I have no response. Nothing shows onscreen. Also, the power adapter of the tablet is dead. So I’ve used my iPad 3 power source and I’m still waiting. Nothing happened so far, no button combination has worked and no heat is emitted from the back. I really hope so that the damn power brick didn’t fry anything inside the logic board since I’m really hating the wait from the Chinese stores.

Best case scenario : It is in a power calibration loop. It happened to me before to a Samsung tablet and I’ve managed to fix it. I’ll keep you posted for anything new.

[Elias Mandouvalos]

After a bit of research, I’ve managed to boot the tablet. The symptoms were similar to a Galaxy Tab S I also have. There, I had to simply open the back case, remove the battery and insert it again. The problem here, in this particular tablet is that the battery is soldered to the logic board. I had the dilemma to unsoldered it, wait a little to reset and solder it again, or wait for about a month for the replacement. Of course I did the first and voila! we had the wonderful Chinese logo on our screen.

 

For anyone who wants to try :

There are three cables that connect the two batteries with the logic board (white,red,black) . The white is the data (temp etc.), red is the current and black is the ground. If you want to reset it, make sure to de-solder the red as well as the white. Wait for a minute of two, and soldered again. Then, press the power button and if you lucky, you will see the screen on again.

Generally speaking, is a wonderful little budget tablet, but make sure that the battery doesn’t drain itself, cause you will have the need to find a soldering iron to reset it.

[Mohamed Hussein]

I made a registration to the forum, only to say that this is exactly what happened to me, too :).. and I tried the same steps suggested by Elias Mandouvalos.. And it worked like charm 🙂

 

Thank you Elias Mandouvalos you are a life saver 🙂

[steelicon]

This solution solved my battery charging problem. However, I cannot charge in Android but in Windows 10 I can charge the tablet, as well as when the tablet is turned off. Any suggestions?

[Dave Gill]

my teclast x98 air died as well tried the battery thing and nothing there is no way i can program BIOS and this is my second tablet not sure they will take it back again not that i want to it took me about 11 month .i only had tablet 3 weeks fist time before it crashed. any one have another idea as to how i can get tablet running again

[Author]

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