Default Lg G2 Does not turn on

Hi,

I have a LG G2 D805 that doesn't turn on. What happened is that the digitizer broke, so i couln't turn off the phone. So i decided to open it to disconnect the battery and wait for my digitizer replacement to arrive.

When i disconnected the battery the phone turned off, so i reconnected the battery to test it out. The phone didn't turn on.
I connected the phone to the charger and the led flashed red. Again discconected the battery and i reconnected it and the phone turned on (this was with the charger connected and after many tries).

So i disconnected it again to test it out because this is really weird, and after many tries the phone turned on but with a message that the battery was not connected. Tried again, and the phone does not turn on at all, not even with the charger connected.

I think that the motherboard it is blocked in some way, I checked the the battery (it is fully charged) with a multimeter and it gives 4.3v of output.
I checked if the motherboard was getting any voltage, and it is getting 3.7v.

I hope you guys could help me, Thanks!