Unanswered Print Bed won't heat

Hi guys, I have the R1 plus with the xxl smart controller and my print bed just stopped heating mid print and won't heat up now no matter what I set the temp to. I just checked the voltage to the print bed while telling it to heat and is reading completely 0 volts. The power supply is giving 12 volts on both channels so the problem must be somewhere around the main board. Any suggestions? Should I check a fuse, if so, where is it located? I would hate to need to buy another main board.

 

So I just unscrewed the board from the printer and wiggled the power output connector to the heated bed and is now heating up. It must be an intermittent connection at the screw clamp connectors on the ramps, how lucky I am! Like everyone says, if it stops working, tap it, then go big for the hammer! LOL! Thanks for the reply Mark!