A friend of mine has asked me to look at their fridge freezer, which is a samsung RSA1NTPE. It gets down to temperatue and runs ok for about a week then the temperature rises. Had a quick look today and found evaporator was a block of ice! I believe it is a fault with the defrost cycle, either the pcb, defrost sensors or the heater. Does any body have any info on the defrost cycle, what temperature the thermostats open/close and how often the pcb sends an output to the heater? Can I force a defrost output from the pcb? Any assistance greatfully recieved. Also anybody know where to source spare parts for this model.