Why is my ps vita not charging and not turning on (battery is ok)

Ok so I have very strange problem, my ps vita slim isn't turning on and isn't charging light indicator isn't even flashing I watched some videos on youtube and searched on google, ifixit and on other forums and I can't find solution i think the port is working just fine. as I said in title the battery is ok battery voltage is 3,91v. I've tried other batteries , charging it with phone charger , home button + r button + power button combination. and it still not working pls help!!