Heatbed Stuck on After PID Autotune (no replies)

Hi all,

I've built a printer and used a Ramps 1.4 Adruino MEGA 2560. All was going well, i installed a heated bed, it took a couple of minutes to get up to temp, so i did PID autotune, since running the autotune the bed is stuck constantly on, the ramps smells burnt when on, and the LED for the bed is constantly on.

Is the board fried?

Thanks