Chosen Solution

I use it since 2012 with no issue. However starting few months ago, the battery is draining while it is being charged. I use the original charger and usb cable, swapping it with my Nexus 4 charger and cable gets the same result. Now the only way to charge it is by opening the case, disconnect the battery cable and charge directly the 2 cells battery as described here. Asus repair center told me that the motherboard needs to be replaced and will cost me $160. So instead I just bought the replacement motherboard from ebay that costed me $18 and replace it myself using this guideline. Unfortunately the new motherboard doesn’t solve the problem, it is still not charging. Now my question, which other replacement part that likely will solve this problem: motherboard flex cable, audio and usb port charger flex cable or the battery? Appreciate for any advice, thanks.. | Problem solved. Replaced the usb port charger flex cable. Cost $14. | Follow this Guide

Try disconnecting/reconnecting the battery, shouldn’t be a problem for you since you replaced the motherboard but here are directions: Nexus 7 Battery Replacement This worked on a Google tablet that would only charge when it was off and a Nexus tablet that wouldn’t charge.