- Unable to turn on the headphone amplifier/The battery life becomes short.
- Even though the power/volume knob is in the on position, the POWER/CHG (charge) indicator lights up in red.
- Unable to charge the battery.
- Charging time is too long.
- Unable to install the driver software on a Windows computer.
- When connecting to a computer, there is no sound or the sound is not played back properly.
- Sound is interrupted when connecting to the computer.