How to fix my issue describe below ? Tablet B3-A40

Nisal20

Acer 10 Tablet B3-A40 is not powering on. when I put it to charge nothing shows. But while charger connected I press the Power-On button for few seconds then the red light comes and doesn't come any display. I check with the multimeter and shows its charging. Went up to 3.80 volts. Some are saying to reset by pin from the tine hole near the volume. This tine hole is for the Mic. Be careful on this.
Is any body solve this issue, kindly let me know.
Thank you

Nisal20

I feel that you are correct. I'm keep on charging without press power button as some are advice. End of the day I remove the battery from the board and check from multimeter the battery is improved up to 3.85 volts which yesterday was 3.75 volts. Seems to be charging very slow. I have an intelligent charger, could you tell me which connections to use for the battery. Battery has 6 wires. Right side is 2 Reds & Left side 2 Blacks. What are the battery wires has to be use for the Intelligent charge (Nitecore Charger) ? At the moment it's connected to original charge with out disturbing.
Appreciated your advice. Looking forward to hear from you. Thank you.

billsey

I believe the two red are +V and the two blacks are GND. The other two (yellow and white maybe) are the sense pins that are used to detect the charge level, so the charger can back off when you get too close to the maximum. Going over the maximum causes *Bad Things To Happen*.

billsey

Normal charging is done through the reds and blacks and the other two are used to stop the charging when appropriate. I can't say this often enough ... Be Careful! Doing the wrong thing can lead to explosions and fires...

Rudy21

Nisal20 said:

Acer 10 Tablet B3-A40 is not powering on. when I put it to charge nothing shows. But while charger connected I press the Power-On button for few seconds then the red light comes and doesn't come any display. I check with the multimeter and shows its charging. Went up to 3.80 volts. Some are saying to reset by pin from the tine hole near the volume. This tine hole is for the Mic. Be careful on this.
Is any body solve this issue, kindly let me know.
Thank you

Try accessing the boot menu press pressing and holding Volume up and power button.

StevenGen

Nisal20 said:

Acer 10 Tablet B3-A40 is not powering on. when I put it to charge nothing shows. But while charger connected I press the Power-On button for few seconds then the red light comes and doesn't come any display. I check with the multimeter and shows its charging. Went up to 3.80 volts. Some are saying to reset by pin from the tine hole near the volume. This tine hole is for the Mic. Be careful on this.
Is any body solve this issue, kindly let me know.
Thank you

That could be the battery itself (it uses a 6100 mAh battery) as it might not be giving enough power to run the tablet or not charging fully due to its age, also, there might be a connection of the battery problem e.g. the battery plug to mainboard or the mainboards charging part which could be faulty or corroded at the tablet plug to charger part is faulty or corroded (see caption below) open your tablet up and check, clean and/or replace these components.

I would first change the battery (as 4 year old batteries do fail and can cause all sorts of problems) as they are available for about US$55.00 and see this guide of how to open your Acer 10 Tablet B3-A40 tablet and try that. The Acer Iconia One 10 (B3-A40) is pretty simple tablet running Android 7.0 Nougat with the 1.3GHz MediaTek MT8167 quad-core, 16GB or 32GB internal storage with an expandable microSD card of up to 128GB and 2GB memory and if you have the right tools and expertise you can open it and change the battery and clean its components. 

Nisal20

I feel that you are correct. I'm keep on charging without press power button as some are advice. End of the day I remove the battery from the board and check from multimeter the battery is improved up to 3.85 volts which yesterday was 3.75 volts. Seems to be charging very slow. I have an intelligent charger, could you tell me which connections to use for the battery. Battery has 6 wires. Right side is 2 Reds & Left side 2 Blacks. What are the battery wires has to be use for the Intelligent charge (Nitecore Charger) ? At the moment it's connected to original charge with out disturbing.
Appreciated your advice. Looking forward to hear from you. Thank you.

billsey

I believe the two red are +V and the two blacks are GND. The other two (yellow and white maybe) are the sense pins that are used to detect the charge level, so the charger can back off when you get too close to the maximum. Going over the maximum causes *Bad Things To Happen*.

Nisal20

If I charge directly(not through the motherboard) from a intelligent charger, how do I give the power. Means, has to give ( +) from the charger to both Red wires of the battery? And same as for Black. 'Cause battery has 6 wires. Looks to me that two small batteries has coupled together.
Appreciated your details. Thanks

billsey

Normal charging is done through the reds and blacks and the other two are used to stop the charging when appropriate. I can't say this often enough ... Be Careful! Doing the wrong thing can lead to explosions and fires...

oeliry

Press and hold the Volume up button, and then press and hold the Power button. Release the Power button after 3 seconds. Release the Volume up button once the device powers on. Use the Volume up and down to navigate through the Android recovery menu.

Nisal20

This is call Hard Reset. This has more options to do step by steps to diagnose performance issues & etc. Anyway as so many are commenting to do so,  I also tried so many times, kept more than 3 seconds but didn't work for me. Some of them may have been solve the issues. If the motherboard doesn't take power in nothing can be done. But charging will do, nothing display about it. Multimeter will show the charging level. Some are commenting to press through the tine hole near the volume button, It's actually the hole for Mic. Be careful about it.