Noticed every so often that the temp would raise in freezer for short period did some temp monitor and found defrost cycle would be good for several times 30 min on 8 off than after a few it would be 4 hours on( or at least the temp would not go back down for 4 hours. replaced defrost timer and still have the problem. I suspect thermostat --when the compressor runs the freeze and refrig works great. Not sure what the Refrig Control PC board does -- Does anyone have any recommendations and the problem is erratic and does not happen every defrost cycle.