Google nexus 7 will not power up - Google Nexus 7

Press and hold Volume Down, and then press and hold Power simultaneously until the device turns on.

Hope that helps!

The battery connector in the Nexus 7 (2012 model) is notoriously problematic. Sometimes dropping the device can cause issues that prevent the Nexus 7 from charging altogether. A hard reset may not work. Fortunately, it is quite easy to fix.

However this will void your warranty.

Pop the back of the Nexus 7 case open by pushing a credit card or guitar pick or small screwdriver under the edge of the black plastic case. Start from the top and gently pry the case open, working your way around. The back of the case will come off quite easily. The battery occupies the bulk of the left-hand side of the unit, and a group of six wires come out of the top of the battery to a connector on the circuit board. Gently push the plug out of the socket connector, wait 15 seconds, and push it back in. Snap the case back on and plug in your charger. You should now see the battery charge image appear.

Nexus 5/5x won't turn on even the battery is fully charged and the phone connected to the power outlet. Find the best troubleshoot checklist to fix the dead LG Nexus 5/5x. There are several threads and forums asking the solution for Nexus 5/5x power problem. Check a troubleshooting guide to fix a Nexus 5/5x which refuses to turn on, before you rush to the repair store.

Boot the Nexus 5/5x in Recovery mode Even your Nexus 5 or 5x is not charging, you can still boot the mobile in recovery mode. Recover mode is a factory mode of Android mobile which boots the mobile in factory mode.
A recovery mode can help you to restore your phone in factory settings and get rid of inconsistencies that might be causing the problem. Here's how you boot nexus 5 in recovery mode.

1. Press and hold the Volume Down and Power keys together until seeing the logo.
2. If the screen lit up and display some text, it is almost certain the problem was with the firmware.
3. Use the Volume Down button to toggle and highlight the option Recovery mode.
4. Press the Power key to select it,
5. Hold down the Power button and press the Volume Up key to display the Android system recovery menu.