How do I replace charger/power connection on Inovix IDP-1020 DVD player?

The pin on the DVD player for connecting the power supply has disappeared inside the player. I have managed to remove the bottom metal cover, and release three sides of the 'motherboard', but I am unable to release the fourth side, where the lid is hinged to the base. The pin in question is on the corner of the side I cannot release. Any help would be appreciated.

Many thanks