Have an american style fridge freezer model as above.
6 months ago the fridge temp rose dramatically so got an engineer out. He replaced the fan. 2 weeks later same thing happened, replaced the thermistor. Same thing happened, replaced the computor board. Same thing is happeneing again… and have lost the number of the engineer.
your post reminded me to update a thread I posted in back in late 2006. Please see Samsung RS21DGRS thread for more info.
I’d ring Samsung on 0800 988 0123 and register your request for the extended warranty (5 years from date of purchase) and then the replacement evaporator assembly, thermistor fuse etc.