Printbed not heating up Ramps 1.4 (1 reply)

Hi, there, I've working on my RAMPS 1.4 and had the problem on my printbed. The voltage across D10 is 12v and the hot end works properly, but the voltage across D8 is 7mv and the printbed is not heating.
I think there's problem with the Mosfet but I'm not sure whether it's on the RAMPS board or in the Arduino Programming?
My voltage source is 12V 5A.
Thanks for reading!