Casio CTK3400SK User's Guide

To perform a factory reset, turn off the keyboard, then hold down the "Tone" and "Rhythm" buttons while turning the keyboard back on. This will reset all settings to their factory defaults.
First, check that the power adapter is properly connected to both the keyboard and a working electrical outlet. If using batteries, ensure they are inserted correctly and are not depleted.
Use a USB-MIDI cable to connect the keyboard's USB port to your computer. Install any necessary drivers, then configure your music software to recognize the keyboard.
Press the "Function" button, then use the "+" or "-" buttons to adjust the transpose setting. The display will show the number of semitones you have shifted.
Use a soft, dry cloth to wipe the keyboard. Avoid using water or chemical cleaners that could damage the surface. For stubborn spots, use a slightly damp cloth.
Press the "Song Recorder" button, then play your performance. Press the "Stop" button to end the recording. You can playback by pressing the "Play" button.
Yes, plug your headphones into the "Phones/Output" jack on the back of the keyboard. This will disable the built-in speakers.
Press the "Function" button, navigate to "Touch Response," and use the "+" or "-" buttons to select the desired sensitivity level.
Check for any physical obstructions. If the problem persists, a factory reset might help. If not, consider contacting Casio support for repairs.
Press the "Tone" button, then use the numeric keypad to enter the number of the desired instrument sound.