Hi there and welcome!
Howdy. My MES30 quit at the end of a 12 hour smoke last fall. (the silver front window model with flat recessed LCD control panel on front top edge). It was running along just fine and the next time I went up to it, it was off and would not turn back on. LCD display was off, no power. Checked my house electrical outlet and it worked fine. Is there a fuse in the back of the smoker? I opened up the back panel and all I can see is the main control board. To me it looks like it isn't getting power at all since the display doesn't turn on at all. I also tried plugging in a spare LCD control panel that I got because the original had a bubble in the protective coating. The backup LCD control panel didn't work either, so I'm assuming there is a fuse somewhere that is buried within the unit, or the main control board is shot. Any suggestions? Thanks!!
Dr. K mentioned made some good points above.
Since you have no power it could be anything from loose wiring, bad circuit board, or a bad controller.
If you inspect it to ensure that all wires are connected well (including the ground wire) then you may have a bad circuit board or controller. There is no real solution for this other than simply replacing the parts and seeing if it works :(
You could just go the route of a straight rewire and use the MES with a 3rd party PID controller like the Plug and Play PID controllers from Auberins.com.
The idea is that you rewire the MES so that the electricity bypasses the circuitry and will simply cause the heating element to heat up.
You plug the MES into a PID controller. You plug the PID controller into the wall and put the smoker temp probe from the PID controller inside the smoker and the PID controller will cut on/off the electricity to the MES according to the set temp you put in the PID controller and the heat reading from the probe. Very simple.
Here is a post I did that would walk you through a rewire of an MES if you decide you want to go that route. Also know that the rewire and a PID controller will give you better controller and more accurate temps then what the out of the box MES controller can do. For Smoke you will still want to rely on the AMNPS and pellets.
http://www.smokingmeatforums.com/t/267069/mes-rewire-simple-guide-no-back-removal-needed
I hope this info helps :)