The NDR 1062 has a 'limp mode' of operation.
If temp sensor fails.....it will continue to operate/cool until repaired.
You can test thermistor.....
Unplug the two wires on lower control board (upper left side P2---2 pin connector)
Place bulb end of thermistor in glass of ice water (more ice than water)
Wait 10 minutes (33*-35*F temp) then check resistance on wires (where they go in connector)
8000--10,000 ohms..thermsitor is good.
"Snip the Tip' is good way to repair
Also has a 'Low Ambient Control' (LOC On/Off switch). In ON position it keeps food section light ON which adds heat to compartment which causes fridge ON cycle to last longer causing colder temps.
Open food section door and check if switch is ON.....on bottom of upper panel