My Phone is dead, now it is not powering on.

I tried to charge my battery of my nexus s from another local charger. . . but it made my phone dead.

when i check supply pins of phone when positive and negative of battery comes in contact with device's pin with my external power supply and power it on. .

it doesn't power on. .

I took my cellphone to repairers to get it checked. they told me it's problem of power ic

I myself is a electronics engineer. so please guide me it is exact problem of power ic or something else. .

Hope, my post will be seriously taken into consideration.