I’ve written enough about the Asus Memopad HD 7 that you can probably surmise I’ve had a few issues with them. Fortunately the fix is usually simple, and in the case of a Memopad that won’t charge even after you did my battery fix, that’s true as well.
It started with my observation that the USB cable fit rather loosely into my sons’ tablets. I cleaned out the mini-USB port with a wooden toothpick, which is a common fix, but it didn’t help–the cable still fit very loosely and the device wouldn’t charge.
Then I tried other cables. I found most of them didn’t work either. If I set something heavy on top, they would charge for a while, but doing that caused the cables to wear out in a matter of weeks. Finally I figured out the tablets are just picky–or at least they are once they get some age to them. The charger for the Moto E, which has a hardwired cable, works fine. So does some other random cable I had that I never used for anything else because it happens to be so short it’s not useful for anything else. I bought some new Monoprice cables, and while they’re fine for data transfer, these Memo Pad 7s don’t like them for charging.
I really hate to say try every USB cable in the house, but… your best first step is to try every USB cable in the house. And if you have to buy a cable, buy something locally, ideally in a store that will try it out with you before purchase. If you don’t have a store with that kind of service near you anymore, then buy a cable and try it out in the parking lot in your car right away before driving home. That way you can exchange the cable right away, or get a refund, if it doesn’t work any better than what you already had.