Hello, N5EGX...honico here...
Repair is not happening for Hiebook -from a 'factory' or service center. It's been a while since your post -and we've maybe talked since then, but with different credentials.
In the mean time; in case it's still knocking around:
Unplug the unit (from anything).
Remove the battery.
Plug in wall wart.
Using a paperclip, reset the unit -but do so with it powered off. Hold it in for a couple secs (central hole in back, near the word "Korea", label).
Power on (if it's not already on) and "walk the dog" -calibrating the screen.
If nothing happened, zip, then there's one thing to look at (internally) -and reply, I'll walk ya through.
If it powered on:
With unit still powered on, plug the battery in.
If unit dies: battery is bad. Replace with discarded (but good) cellphone battery: 3.6~3.7V, 1200~1800mAh, substituting the little circuit card (wrapped w/ battery).
If the unit didn't die, turn it off (still plugged in).
Install battery: power on.
-If it powers on, then it may just be a weak battery...or nothing at all.
-If it won't power on, it's definitely the battery.