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Help Nexus 7 (Gen 1 - 2012) only boots when connected to external power

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bazzaman

Newbie
Normally I shut my Nexus 7 (Gen 1 - 2012, ME370T, Android 5.1.1, build LMY47V) down whenever I recharge it and so re-boot every few days or so.

Yesterday I went to re-boot and nothing happened at all. Tried holding power button for 1 minute or more. Still nothing. Tried holding volume down button and then power button - again for up to 1 minute. Did same using volume up. Still nothing.

So tried with the tablet still connected to external power. Worked fine, even if I disconnected external power just after the initial splash screen started.

Battery seems fine. Holds a charge quite well and voltage is typically showing around 4 volts (incl. when not connected to external power).

Any ideas?
 
Hey @bazzaman, I don't have exactly that problem with my 2012 N7, but I do have what I think is oddness/weirdness when trying to boot into fastboot/bootloader mode while the USB cable is plugged-in (something I don't have an issue with on my other Nexus devices).

So, that's kind of the reverse of what you're seeing (I can boot it up just fine when not connected via USB).

BTW, would you like me to move your thread to our N7 area?

There might be other folks there that have seen something similar to what you're seeing...
 
My N7 has the same problem, I think it's due to battery voltage after a deep discharge.

Simple keep your N7 charged as much as possible.
 
Thanks for the reply.

It might be due to a deep discharge (although I never really went that low to my knowledge). In any event, the design of these batteries (and their onboard electronics) are supposed to protect against doing such damage. The battery is rated at 3.75 volts and the device shows the voltage as around 4.1 volts when charged and probably never gets down as low as 3.75 volts.

Keeping the device reasonably well charged doesn't solve the problem either. As I said, it will only boot if connected to external power (and actually in charge mode; rather than fully charged and ended charging) . If it gets to a fully charged state I have to momentarily disconnect the charger and reconnect (to kick it back into charge mode) before it will boot.

I've also found that it boots fine when connected to a portable battery pack (as opposed to a wall socket charger).
 
Perhaps its the over-charging protection circuit / logic that's gone on the fritz and a battery replacement might fix this (since I believe that circuitry is on the battery itself). Although that might be a non-worthwhile solution given it's a 1st gen device...:dunno:
 
It seems that your N7 has a different issue. Personally I could try to reset the tablet to factory setting to see if the problem persists. Otherwise it might be hardware related.
 
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