samsung RSA1NTPE

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.

The heater plug will have been pushed out by ice in the freezer. You need to fit a defrost sensor too.

Hello Guys, I work on commercial equip mainly, but my own Samsung RSA1NTPE Fridge Freezer is playin up it's less than 2 yrs old. It's not defrosting, I've tested the defrost element from to pcb plug, in turn tested thru the defrost Klixons and got 165 ohms. This seems ok giving 1.5 amps'ish. Do you think it could be the main PCB ? Any help appreciated, Ta. Pieman.