Digital pin 8 powered on all the time

I am running a home brew 3d printer using the Arduino MEGA 2560 board and 1.4 RAMPS. The problem being that the digital pin 8 which powers the heated bed is on all the time so when I start the printer the table immediately begins to heat without reference to the board. Is this a hardware issue or is there something in the firmware? I have tried various firmware but nothing makes any difference. Any ideas out there? thanks all.


Digital pins should all default to inputs when the MCU is powered up.
Perhaps your pin 8 has been damaged.

You should never draw more than 20 mA from any digital output.