It wont open up

When I’m trying to charge my laptop the charger went from 19,5V to 0.7-1.2V. I don’t know why I tried with another charger and it did the same thing, i think there is problem on motherboard, not from the side of charger. I looked with electric meter between the cable of charging port and motherboard. And the short circuit is on the side of motherboard. Can someone give me some ideas what can be broken?