I noticed you used the word attempt. Were you finally able to get a perfectly (or at least acceptably) functioning controller?
Nice catch. The "issue" isn't completely straightened out and it got too cold in MN to mess too much with this after I got he last pair. But, the original issue was that the control panel and meat probe showed a variation of 30 degrees which also varied from my Maverick. The meat meat probe also differed from the Maverick by 10-15 degrees. Even though I relied on the Maverick to determine food IT, the spread and inconsistency of the controller temp made it hard to reliably produce consistent results. With the latest replacement parts, the controller and the meat probe read within 5 degrees of each other, but they read about 35-40 degrees higher than the Maverick. I have to set the MES to 185 or so to make sure the temps don't get into the 275-290 range. Perhaps the controller is not calibrated for the temp probes in my unit. This could happen if
MasterBuilt changed temp probe types/part numbers. To address that would probably require a new box and like was posted in your "Open Letter" thread by another user, I'm more interested in smoking meat than replacing parts on these things.
In the end, I kind of gave up on it for now, purchased a Cookshack SM045 and have been using it. The temps on the SM045 are within +/- 2 degrees of what the Maverick shows and it holds the set point temp to within +/- 1 degree for the entire smoke. It's much easier to produce consistent results now. Even with the ambient temps of -20F it held consistent temps and in a driving snowstorm I wasn't concerned about frying the controller.
I might start tinkering on the MES40 again in the spring.
Ron