If your newly purchased power supply is not responding to any button pressing or knob spinning, it may be in lock-out mode. The lock-out function can prevent accidental button pressing errors but many times the user doesn't even know it's there!
Much like a safety lock, it is there to prevent any data change to the device without the operator's knowledge. To find out if your device is in lock-out, first check its user manual to make sure the function is present. From there you can follow the directions to disable it. For example, the Korad power supplies have a dedicated button for the lock-out function. Holding down the button for 3 seconds will toggle the function on and off.
Side Note: For Korad programmable models, the control panel will not function when plugged into a computer. In this case the Korad software takes over and all changes must be made through the computer.