My T98Pro doesn´t charge the battery

[Ferchica]

Hi all,

I think this is my first post in your forum but I have been reading you before I brough my tablet back in Nov’15, I love this comunity and information I found here was very helpful first to decide which tablet to buy and later on to fix the problem it had.

 

Now I am facing a new problem I have’nt seen information about, my tablet doesn´t charge the battery, every works fine but tablet is unable to charge the battery.

I tried to remove the battery to do a hard reset and reset it, but still doesn´t work.

With a multimeter I as able to checl that 5v from charger are in the mainboard by measuring them in the internal volatge regulator that converts 5.2X V from charger to 5.0V, but this voltage doesnt arrive to the battery, battery is 3.7XV no matter if charger is connected or not, and without battery but charger connected voltage in battery pads is 0 V.

 

So I assume that I have a HW problem in the board but I am not able to find a place where buy a new main board, I contacted with vendor but the only solution I got from them is to ship back the tablet for repair, and I won´t this, I won´t spend 50% of cost of the tablet to repair this chinese bad quality stuff

Maybe it is an stupid thing like a blow fuse or something like that, maybe not, somebody has the schematic for this board Camellia_v10 or a deeper knowlege about can help me??

Thanks in advance

PS. With Battery removed and charger in, tablet doesn´t work

 

 

 

 

[Sergey]

Check voltage on usb port when charger is disconnected. If there will be 5v, it means that otg chip is probably broken. You also can turn off the tablet, give him a rest and then try to charge.

[Ferchica]

Thanks I will follow your suggestion and post the result

[Ferchica]

Tablet has been a couple of days with battery unsolded, I solder it again, battery still has 3.7 V enough to show it the logo and battery low icon before it shut down again. Trough the OTG before press power button, no voltage but after press on button it shows 5.06 V without an load. Tablet still doesn’t charge the battery. I have not idea about next step

 

[Sergey]

Its important, did you test in usb mode or usb otg?

[Ferchica]

I did it in OTG mode

[Sergey]

You should test in usb mode, like you want to charge him.

[Ferchica]

Sergey first of all, thank you for your time help me with this problem.

Checking USB mode I was unable to see any voltage, multimeter show 0 V

 

[Sergey]

Well, if he shows 0v, that mean it`s not otg controller problem. So i have no idea what can it be. The only thing that i can offer is make a port on tablet and charge the battery directly with charger like imax b6. Or you can try send it back on factory if you buyed tablet in shop like gearbest or similar. They usual have 1 year warranty.

[Ferchica]

Finally I got parts to fix my tablet.

I soldered a cable to connect an external charger circuit and it seems to works.

I am not the best with the iron 😉 , but circuit works and it delivers  around 4.19V@1A, I expect to take longer to charge the battery but at least it is alive again

Here you have some pictures, I hope it will helps somebody

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