My screen was broken so unable to switch of phone so switched screen with power on.

When the screen was replaced everything seemed Ok but the digitizer/touch did not work so I thought I had zapped the screen.

I then disconnected - reconnected the battery and cold rebooted the phone and that got the digitizer working.

So I suggest that You disconnect the battery before connecting the new screen to ensure the power is off

Ingemar 1508027