Onda V972- Bricked. Please Help Unbrick - Forum

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Onda V972- Bricked. Please Help Unbrick

Bricked Onda V972 by trying to install Cyanogenmod and 12 months later it does not turn on.

poliosynthesis

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2014/10/16 - 10:18

Hi,

Last year I bought an Onda V972 and after several weeks it slowed down considerably and became very crashy, so I decided to install the unofficial cyanogenmod build for allwinner A31 devices from Christian Troy:

http://www.slatedroi...4-04-19/page-45
However in my rush I missed a step and ended up killing the screen drivers and bricking the tablet. After that I put the tablet down and never picked it up again, until today when I tried charging it and the battery didn't hold a charge and didn't turn on when plugged into the wall. Do you guys have any idea what could be wrong? Or any idea how I could fix it?

Thanks [Image Can Not Be Found]

admin

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2014/10/16 - 10:29

Hello,

If that battery life issue did not happen before, it may just be the end of life your battery as it can't hold capacity anymore and refuses to recharge.

It's usually recommended not to store a battery fully discharged see http://www.powerstream.com/Storage.htm and http://www.bhphotovideo.com/find/Product_Resources/Battery_Guidelines.jsp)

Can be worth a try leaving the charger plugged for a few hours and see if the battery revives. If you see the charging logo, try reflashing a proper firmware on your tablet, make sure the charger is on when you flash again.

Cheers.

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poliosynthesis

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2014/10/16 - 12:04

Thanks for your quick response. I have noticed that when I attempt to turn the tablet on, a high pitched noise is emitted. Also should it not revive within the next couple of hours(or overnight), do you think the most prudent course of action would be to replace the battery? If so, do you know whether the operation to replace the battery is particularly difficult(I have no soldering experience btw)?

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2014/10/16 - 12:49

Based on the high pitched noise, there may be some extra hardware damage, can't say for sure.

If you manage to get a display working again after charging it's probably worth to try reflashing proper firmware.

About the procedure to change the V972 battery, I remember seeing some posts on the topic already in our V972 forum section, you'll have to search for it. But I don't have experience with this kind of situation so I can't recommend it as a definitive solution to your problem...

Cheers.

cracktech

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2014/10/17 - 13:10

poliosynthesis said
Thanks for your quick response. I have noticed that when I attempt to turn the tablet on, a high pitched noise is emitted. Also should it not revive within the next couple of hours(or overnight), do you think the most prudent course of action would be to replace the battery? If so, do you know whether the operation to replace the battery is particularly difficult(I have no soldering experience btw)?

Replacing the battery does not involved an expertise in soldering iron. 3 points to unsolder only. But the tricky part is the dismounting of the battery from the back of the "backlighting panel", normally white plastic) It is attached via double sided tape you cant force the separation of battery from the backlight plate by using sheer brute force it will break the battery into 2 parts or more. You will have to use thinner to softened the adhesive tape (but at the risk of getting it onto the screen and reacting/dirtying the screen, care has to be taken here)

But I doubt it is your battery issue , a normal battery will charge after attaching to a charger no matter how bad the condition of the battery is. This has got to do with your earlier flashing error method it wiped off the /ubin loader/loader before the kernel and therefore it doesnt even know what battery charge is available hence you cant even reflash it as yet. Please go back to Slatedroid Forum and seek for unbricking method from CTroys post or ask one of his lieutenant there. There is one particular moderator who is very knowledgeable about unbricking (I was a frequent contributor to Slatedroid at one time/ together with Omarahum,now dont like the Forum.)

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2014/10/17 - 13:21

Thanks for the followup cracktech.

You're probably more knowledgeable in battery technology and electronics than I am. I suspected that a faulty battery could even prevent the circuit charge to work, but that was probably a false assumption; unless there was a short circuit or something really bad happened.

Cheers.

cracktech

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2014/10/17 - 17:53

I concur with admin that there is also a possibility that another circuit is effected thus giving the high pitch sound.(but also note that on the battery itself there is a small circuit board, with capacitors and resistors and a power IC) that is why you should not force/pry the battery for fear of breaking this fragile circuit board if it is found that the battery is not the culprit , it will save you money and time.