I have 7 yr old Samsung side-by-side refrigerator with twin cooling (1 evap in fridge and 1 evap in freezer). It started misbehaving by getting too cold in refrigerator compartment. Thermostat reading on front LED panel said the temps were normal but used a thermometer and frig temp was 10-20 degs colder. After several days it had opposite problem and both refrig and freezer compartments were way too warm (60 - 70 deg). I pulled both evap covers and both evaps were frozen over, ice had blocked up air ducts adn wasn’t getting air circulation.
My first suspicion was the thermisters were getting out of spec. I ohmed out from the main control board connector, and all thermistors are OK. I ohmed out both the freezer and refrig defroster heater circuits and both look OK. I put into forced test mode and forced on defrost in both compartments, and voltages look good at PCB connector.
So, defrost circuit seems OK, but yet it frosted up, so I’m thinking it is a control board issue. A bad control board can also cause bad thermistor readings even though thermistor sensor is OK, I’ve heard. My theory is it was confused about the temperature, and didn’t shut down compressor, eventually freezing up, blocking air flow, and getting warm.
I’m thinking of trying to swap out the main control board.
Can anyone think of anything else that might cause these symptoms?
thank you in advance.