Hi there and welcome!
So you have a couple of options. You can try more of the
Masterbuilt controllers and do what you are doing BUT the controller is 1 of the 2 most common failure points of the MES... as you are finding out.
The other option is to
do a very simple rewire (cut ends of 4 wires and splice to become 2 wires) to your smoker and use an alternative controller like the one posted on
Amazon or use a PID controller.
This controller from
Amazon behaves in a very similar manner that the stock MES controller behaves in:
You still MUST rewire the MES to use this controller.
After the rewire of the MES the cord of the MES will simply feed power to the heating element, it is now dumb and is either on (plugged in) or off (unplugged).
So after the rewire u plug the dumb MES' cord into this kind of controller and then plug this controller into the outlet and set a temperature. Next throw the temperature probe into the smoker and the controller will cut power on/off to the MES cord in order to hit and try and maintain the set temperature as it measures the temp in the smoker.
This kind of controller is pretty simple, it will swing up and down around your set temp like the original
masterbuilt controller BUT will possibly be more precise and have lower temp swings... you wont know until you try it.
The PID controller option is MUCH MUCH more precise but costs more money.
If you don't already have the tools, supplies, extra parts, and the knowledge, then buying a plug and play PID controller is more cost effective and simply a better option than building one.
For $150 you can get a true PID controller here:
Auber Instruments, Inc. Multi Purpose Controller [WS-1510ELPM] - The WS-1510ELPM is a versatile temperature controller to have in your home. It can be used for various applications such as Sous Vide cooking, controlling an electric smoker, making yogurt, dough proofing, controlling the...
www.auberins.com
The PID controller will hook up the same way as described with the
Amazon controller BUT the PID controller can hold within 1-3 degrees of the set temperature once the P-I-D parameters are tuned and set (u can run auto tune to get close or ask someone here for their parameter values).
The PID controller seriously turns your smoker into a completely different animal that is much much much better than the MES you bought brand new.
With such tight temperature control you can have your smoker operate from 1-275F degrees with ridiculous precision.
This means no temp swings to ruin sausage or bacon by accidentally swinging so hot the fat starts to render. This means doing cold smokes in cold areas of the country where you may want to set the smoker to 20F just to create draft to move the cold smoke to keep it form getting stale and leaving horrible stale flavor on your items.
Also if u get this exact PID controller you can move up to a MES40 and rewire the MES40 and be ready to rock and roll.
To me the BEST thing to do is to buy a used MES40 for like $40-50 on craigslist, rewire it and slap this $150 PID on it and you have a smoker that is less expensive and 50X better than a brand new MES40.
In all these rewire situations you lose the ability to put woodchips in the smoker and have them make smoke BUT 99.9% of MES users dont use that and instead use the A-Maze-N Pellet Smoker (
AMNPS) tray or tube to produce perfect, no hassle, long running smoke for hours so it's not really an issue.
I've thrown a lot at you here so I'll stop rambling now hahaha. Let us know if this makes any sense and if you have any questions... oh and if u want to read about the rewire job you can here:
https://www.smokingmeatforums.com/threads/mes-rewire-simple-guide-no-back-removal-needed.267069/