I have had the same problem with two of these mande late 2016/early 2017. The "EC" is error code and is generated when the compressor overheats. The compressor is not pumping the refrigerant through the system and will eventually overheat and stop with the EC code. Unplugging/replugging will restart the unit but it will again overheat and stop with EC code. Nothing to do with the circuit board - it is doing its job. Call the toll free number on the silver label and they will refund your money (less shipping and tax). There is no "fix" for this - defective China made trash.