I just posted a solution that has been working for me now for two years. See: https://us.community.samsung.com/t5/Kitchen-and-Family-Hub/RF23HCEDBSR-AA-freezes-need-to-defrost-every-4-6-month/m-p/1714607#M39999 The fridge ran okay for about 18 months and then I started getting the fan noise from ice buildup. It was a long slog to figure out what needed to be done. At least in my case, my home-brew solution was very effective. The source of the problem was a bad evaporator cover seal. My assessment was that this was due to wires that were improperly routed at time of manufacture. Check out my other post. Good luck.
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