Just a side note...all refrigerators have evaporator coils that are supposed to get frosty when the compressor is running. A healthy frost pattern on the coils is one of the primary things a technician looks for to assure a properly charged sealed system. When the cover panel is in place and the fan is running, the frost does not sit there and collect on those coils, it is passed along to the fridge as cold air. If you sit there with the panel off looking at the coils, air cannot flow across them any longer so the frost accumulates. Lesson 1: Do not run the fridge with the panels off.
If 3 days later you come out there and see frost covering the coils again, it means the board is not doing its job and turning on the new heater after every 10 hours of run time. Replace that board and you should be ok.