A MIDI keyboard is essentially a piano-style digital keyboard used for generating and forwarding Musical Instrument Digital Interface (MIDI) commands or signals to other devices, such as a computer. The computers speakers can then play the signals sent by the MIDI keyboard. A MIDI keyboard sometimes starts to have glitches, in which case you have to clean its inside thoroughly. If the problems persist, you may need to bring your keyboard to a specialised technician.
Clean the outer body of the your MIDI keyboard with a sponge and warm water, removing any dust or grease.
Pull the knobs that hold the top portion of the keyboard's plastic body up. Do it firmly but carefully so not to damage the keyboard.
Remove the top portion from the bottom portion of the keyboard using a screwdriver. Now you should be able see the inside of the keyboard.
Remove the circuit board of your keyboard and clean it thoroughly using cotton swabs and an-alcohol-based cleaning solution. The circuit board is a thin board that stretches along the keys of your keyboard. You can remove the circuit board by unscrewing the small screws that hold it to the keyboard's frame.
Remove and clean the keys of the keyboard (you can remove a key by slightly pulling it upwards), paying particular attention to the places where the keys interact with the keyboard. Like with the circuit board, use cotton swabs and an-alcohol-based cleaning solution. Dirt on the keyboard keys is a common source of a MIDI keyboard malfunction.
Reassemble your keyboard and test it. if any glitches persist, consult the keyboard's manual or bring the keyboard to a specialised repair shop.