Hello,
I have owned a chinese tablet some years ago, a Cube F7 or something. It did not start too and there was a way to bring it back to life by introducing a needle or better, a paperclip into a very little hole somewhere in the tablet. The hole was there especially for forcing the device to life.
Maybe your F5 also has such a hole?
If it has and poking in it does not work then poke again for alonger period.
Succes!
