Lenovo Tab 2 a7

viewer

Senior Member
Sep 14, 2012
9
0
I was hoping someone with some technical knowledge may be able to assist me with my tablet not working?

I cannot get it to power up after charging, in any way, despite trying the many different methods of holding down the on/off and volume up/down keys.

I have also seen the references to remove the battery, which I have also found to not work for me.

I am trying to determine whether in fact the usb charger point is actually supplying power to the unit, thinking there may be a problem with the adapter on the motherboard?

I have tried many chargers, all with no success.

This is what it looks like where you connect the power cable to the tablet, and I was wondering if someone could tell me, what points can I put a multimeter on the correct areas to see if the connector is my possible culprit.

Can someone suggest some locations, what outputs it should display?

Battery is a L1CP3/87/100 L13D1P31 Li Polymere Charging Limit voltage 4.35VDC Capacity 3450 MaH/13.1wH. I am using a 5V charger and cable.

Many thanks

tVPyeVk.jpg
 

Traveller

Administrator
Staff member
Jun 16, 2012
2,816
971
Are you able to get into EDL mode (volume up while plugging a USB cable into the tablet)?
 

Traveller

Administrator
Staff member
Jun 16, 2012
2,816
971
Lenovo generally uses the MicroUSB port for charging, if my Tab 4 is any indicator. It therefore will follow the USB standard (see pinout below). Unfortunately for you, the connector itself is rather robust. While they can fail due to constant removal and insertion, in general MicroUSB ports are rated for 10,000 such insertions. So unless there is a defect in the connector, it's very unlikely the connector itself is the problem. That leaves either the charger, the device's charging circuit, or the battery as the culprit. I'm personally inclined to believe this to be a battery issue.

micro-usb-pinout.jpg


NOTE: Even if your tablet has a dedicated AC adapter with a barrel plug connector, the probability of the connector failing, while higher than with a MicroUSB connector, is still not as likely as a battery issue.
 

viewer

Senior Member
Sep 14, 2012
9
0
IwRdaTT
Thanks for the reply, yes it does charge via a usb 5 volt 1 amp charger.

Since my last post, I bought one of those usb doctor devices..
https://i.imgur.com/IwRdaTT.jpg
Imgur
usb doctor

When I connect with wall charger only connected, I get the correct reading of 5 volts and no milliamps, as nothing is connected to it.

I then connect the usb cable charger to the Doctor, and again, as it is not yet connected to the Lenovo, it still shows 5 volts and no milliamps.

I then connect the charger to the Lenovo, but nothing changes, as the 5 volts is still shown, but milliamps is 0000.

Does this suggest the charger port is stuffed?

The micro usb port is so small, that the bottom end does not let me see those pins to be able to check any voltage, but having said that, I tried the same charger and cable on te mobile phone that uses the same cable, and it shows the mobile as drawing the 1 amp when it is turned on and connected...thus I think charger and cable are ok.

I just need to determine whether the micro usb slot on the Lenovo is the culprit, or somewhere else?
Thanks
 
Last edited:

Traveller

Administrator
Staff member
Jun 16, 2012
2,816
971
Again, I don't think it's the port itself as it's really difficult to damage. Since the charger itself is apparently working correctly, either the charging circuit has failed or else the battery has. How old is this device?
 

viewer

Senior Member
Sep 14, 2012
9
0
Thanks...3 or 4 years old, out of warranty.

I have not purchased a new battery to check, just in case I got that, and it was something else stopping the charge?
 

Traveller

Administrator
Staff member
Jun 16, 2012
2,816
971
The battery is the easiest thing to check by replacing it, and the first thing likely to die after four years. Replace it.
 
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