I believe I fixed my 2018 3-door refrigerator fan noise problem. It has not re-occurred since 8-2020. But there are more issues involved than I originally knew about. The "noisy fan iced over" was a fairly easy fix once you know how.
But why can't the refrig hold the temp that is showing on the display?
I have learned that if the incoming 120 volt power to the refrigerator "blinks" off and on, which can happen multiple times during a thunderstorm, you must cycle the power to the refrig. And it must be cycled off for a longer off time than a "blink". If you do not do this there is a real good chance "this may result in the processor locking up". I got that quote from a Samsung website troubleshooting guide. The guide also said to "wait for 30 seconds" with the refrig unplugged before restoring power. This is what happened and will continue to happen to my refrig.
But the real issue is when the "processor locks up". The temp display on the door will show the temp of the refrig when it locked up. That temp stays in the display with no alarm indication. But the compressor will not work when the processor is locked up. This will cause the refrig and freezer to warm up over time. The display will only show the last temp before "processor lock up", not the "real temp. This may result in the need to throw out all the food in the refrigerator and freezer. Or worse yet, someone is food poisoned, which can cause serious illness or even death.
The fix should be an appliance (refrigerator) that can reset itself automatically. Otherwise owners are required to have someone "refrig watch" during power "blips" and do a manual reset, if necessary.
I guess I may have to hire a "refrig sitter" if I have to be away for a weekend.
This issue can also cause the icemaker in the refrig section to "freeze over" if not reset in time.
I feel Samsung could fix this if they want to. They know about the processor lock-up issue. The support page I found the info on was updated on 5-29-2019. I guess only time will tell.
My temporary solution is to frequently check my old microwave which has a clock that does not auto- reset when a power "blip" occurs. If the microwave time shows zero I know I need to cycle power to the refrig circuit breaker.
I also bought 2 thermometers that I keep in the refrig and freezer. I just have to remember to check them often to keep my family from getting sick.