I had a power outage with several rapid on/off cycles and when the power was finally fully restored, the fridge side froze all the food. I tried unplugging the fridge for a few mins to reset it, no luck. Tried changing the set point to the warmest setting- no luck. The thermistor tested ok with resistance (Ohm's) changing in cold water vs. heat. I could not see anything wrong on the board visually, but changed it out and fridge works again maintaining above freezing temps. Reprogramming the board was easy as per the directions and video example from this site.
Careful handling the board. You have to "snap" the board at a scored line and it's a little tricky (at least I did on my fridge because that is how it fits in place and is retained). I wore rubber gloves and was careful to not touch the board components.
The freezing also cracked my water filter and the water filter assembly on the fridge side and I had to replace those too.