The keyboard has no sounds of its own – it is only a midi controller. If you have loaded up an instrument and there is still no sound – check the following.
Is the keyboard turned on? (There should be blue lights above all the keys) The power button is at the back, center and down low. You can pull the keyboard towards you a few inches to get your finger down far enough to push it on.
Is the volume up? The keyboard has midi/modulation controls at the far left end of the keyboard that could affect volume. Look for the flat ribbon controller with blue led lights just above the strip. This ribbon controller is most often set to “expression” which is actually, just a volume controller. It can easily be accidentally tapped – especially when using the modulation wheel. Run your finger up and down the ribbon controller and make sure the blue led lights are fully on (that is – to the right)
Modulation wheel. Depending on the sound selected – especially with legato articulations – the modulation wheel is set to dynamics. Dynamics change the selection of samples from whisper quiet playing to full fortissimo playing. – Make sure the modulation wheel is turned up.
Headphone jack/volume control. Make sure the headphone jack is plugged in to the black USB midi interface (to the right of the screen) and that the volume control is at least three quarters full volume. Headphone jack 1 is for the Sony headphones. Headphone jack 2 is for the AKG's.
If using a DAW (Cubase or Logic)
Make sure you are playing the keys within the selected sampled instruments range (eg. not playing above or below the actual range of the acoustic instrument)
Similar to above – check that the keyboard range hasn’t been set to + or – octaves (left side of keyboard)
Make sure you have loaded an instrument on a particular track
Make sure you don’t have a different track soloed
Check your mix level (meters)
Check your sample player level (horizontal volume slider in Kontakt – should be halfway or more)
Make sure that there is only one program open at a time. Having two DAWs open or a DAW and a notation program can sometimes confuse where sounds and samples are loaded.
Check that the midi cable is still connecting the black USB midi interface to the computer. (This should never be disconnected for any reason)
Restarting the Computer. Occasionally, the computer may just lock up and the only remedy is to restart the computer, which can be done by clicking the black Apple sign in the top left corner and clicking restart. If the mouse is locked up as well, the only way to restart is to push and hold the power switch on the back left rounded corner of the mac mini computer. It’s flush with the body, so it can be tricky to find. After turning off – give it 30 seconds and push and hold the button again until the start-up “chord” is heard again.
This should cover most reasons for not hearing sound.