Frigidaire Freezer not freezing

Brand: Frigidaire
Model Number: LFFH17F7HWB
Main Symptom: Not freezing
What happens & when:

Error Code (if any): Hi Temp
Parts or tests already tried: defrost heater and thermostat replaced
Photos / video link:

If the unit is not cooling at all, check to see if the compressor is running if it is but not cooling then check to make sure that it is not frosting over on the evaporator coils. If it is and the defrost heater and thermostat have been replaced then the control board will be the issue. If the compressor is not running then this will be a faulty start device as long as there is 120 vac to the start device.