Tablet's battery not charging?? Solution found!!
Posted 27 November 2012 - 09:06 PM
Posted 06 December 2012 - 10:54 AM
I first charged the two li-ion batteries with a separate universal li-ion camera/phone battery charger I have, to prove they were OK (they showed 3% full), and they were OK. I turned the pad off for this and used a couple of wires and gaffa tape to charge the two cells one at a time whilst still in place in the pad. Once charged I disconnected everything.
My charger is similar to giokspy's here : http://www.slatedroi...post__p__237307 - those two pins he's connected to slide up and down so they can match the pins on a camera/phone li-ion battery and charge it. They auto-sense voltage and polarity which makes life really easy, and they auto cut out when they see a bad cell. In my mind the safest way to charge an unprotected cell.
When next plugged into the pads charger and turned on, the led showed as steady green as the batteries were now fully charged. Removing the charger for 5 minutes pad use, then replacing it gave me a steady red light again, 98% full...and no charging.
So, out with the multimeter. I could see that plugging in the charger didn't affect the voltage across the battery at all, so although the mains adapter could supply the pad with what it needed (9.02volts by the meter), it still wasn't charging.
I took various measurements from the charging circuit, but unfortunately sneezed whilst probing the yellow highlighted chip in surya's post:
I say unfortunately - the pad was turned off at the time, but the red/green flash turned steady red. A quick check of the battery showed higher volts, so it was charging...for 30 seconds, then back to the red/green flash and charging stopped again.
I pressed each of the legs of that chip in turn, and occasionally could start charging for a few seconds at a time...dry solder joint!
Solder iron out, battery positive un-soldered from the board and insulated with tape, charger plug removed for safety, then using my finest soldering iron tip and a tiny amount of new solder for its flux, I re-soldered each pin. Having checked I hadn't accidentally soldered two pins together, I re-connected the battery to the board and plugged in the charger. Steady red light. I started the tablet and could see the battery charge percent increasing. After half an hour the light went green.
I'm going to make a guess here that the people who try the shorting method to fix this issue could be causing a spark in a dry joint under this chip, and it's temporarily remelting the pin to the board, and that's why this strange and potentially dangerous/damaging approach can work for some.
Hopefully more of you will find that a careful re-soldering of this chip will solve the issue for you too - mine's now worked perfectly for a week
Posted 12 December 2012 - 02:23 PM
any solution for q88 tablet
Posted 25 December 2012 - 11:15 AM
Could you please tell me if you find a solution to fix issues related to tablet not charging ?
Thanks and regards
Posted 25 December 2012 - 12:50 PM
Posted 02 January 2013 - 09:17 PM
With the unit switched off and no charger plugged in, I measured the voltage at the GND-VBAT point and read 6.8v.
I then connected the charger and measured again but the reading was still 6.8v. is this correct?, should not the reading with the charger connected be 9v?
Posted 25 January 2013 - 06:10 PM
one is not charging other one is going hot
Both are defective because of this marked in black. 2x5 pins regulator i suppose.
Posted 03 February 2013 - 06:25 PM
Seems that I have a similar problem, I ordered 2 Cube U30GT's, a white and black one. The black functions perfectly, but the white one worked like a charm until it had to be charged the first time....
Since I had two chargers I could easily ruleout a broken charger, the battery also reported only a voltage of 6V (when plugged in and 'fully'charged) while the black Cube reported a 7V.
The suppliers agreed to send a new batterypack whitout sending the whole Cube back, a nice gesture because that meant I didn't have to pay for shipping the tablet back. And it also meant that I would have my tablet working again a month sooner :-)
I received the new batterypack (prod.date jan 3rd, 2013!), replaced the (assumed) faulty one and was happy, I had a tablet again working without a cord :-)
But after the first charge I was again dissapointed to have a non-working tablet - the device says 100% charged but it is not charged at all, pulling out the plug makes the tablet shut-down immediatly.
I opened the tablet and measured the voltage of the battery pack, only 6,8V - I plugged in the charger and measured again only 6,8V so the charging circuitry seems non functioning. I soldered one of the battery leads loose and measured the voltage again, it was jumping up and down between 0V and 8,5V! Unplugging the charger I measured a steady 12,2V
Sending it back will cost me probably more than buying the Li-ION charger that was suggested by eatatjoes here DX - does anybody know if that solution will work with a Cube U30GT?
Posted 25 February 2013 - 05:48 PM
woke up all of them by plugging 5v on the mainboard where batteri connects. but they don t accept charge though.
Posted 15 March 2013 - 06:28 PM
Edited by BitTourist, 15 March 2013 - 06:29 PM.
Posted 16 March 2013 - 01:01 PM
Thx for the inspiration to do this! Now i have usable tablet! Just popped a beer...
Edited by BitTourist, 18 March 2013 - 02:22 PM.
Posted 20 March 2013 - 01:56 PM
while my Tablet is charging fine I am still looking at a charging issue (Freelander PD10 MTK6577).
When I use my tablet as an OTG host, the tablet will stop charging (which is usual behaviour, as the tablet thinks it needs to give vbus to the attached device).
It can also be done via kernel mod, however I would like to ask whether it is possible to add a dc port to the tablet, but which must allow the tablet to sense the charging.
Posted 21 March 2013 - 09:45 AM
Posted 23 March 2013 - 08:59 PM
Posted 24 March 2013 - 11:10 AM
Posted 26 March 2013 - 07:23 PM
Posted 05 April 2013 - 04:24 PM
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