Headphones will not connect to device
The Bluetooth headphones will not connect audio to the device.
Not in pairing mode
Ensure that the device’s Bluetooth is ready to pair with the headphones. Go to settings-> Bluetooth-> connect-> Sennheiser HD 4.50. If the headphones will not go into pairing mode, see below on troubleshooting pairing mode.
Not a NFC-compatible device
A near-field communication (NFC) compatible device allows short-range connection between devices such as Androids or other smartphones. If trying to pair to a non NFC-compatible device, try holding the power button in the On position for at least 4 seconds and it should then enter pairing mode which will allow it to connect to the device.
Headphones will not turn on
The Bluetooth headphones are not responding when pressing buttons and are not showing any signs of being powered on.
Make sure the headphones have been charged with the provided USB cable for a complete charging cycle of 2 hours. Try not to interrupt the charging cycle for the first time charging the headphones.
Faulty micro-USB cable
Ensure the headphones are correctly connected to the USB. The micro-USB plug of the charging cable should be connected to the micro-USB input of the headphones. If the LED lights are not on signifying that they are charging, then the USB cable is faulty. Consider purchasing a new USB charging cable.
Headphones have no audio signal
The Bluetooth headphones do not seem to be presenting sound that you can hear.
Headphones not paired to device
Ensure the headphones are paired. You may need to disconnect the devices and repair them.
Volume is too low
Increase the volume by pushing the volume + button.
Headphones do not respond when buttons are pressed
The headphones are not responding to pushing any of the buttons.
Try restarting the headphones by turning them off and then back on.
The battery may need to be replaced. The battery is located in the left earphone. First, remove the ear pad from the left earphone. Then, use a phillips head screwdriver to remove the screws from the plastic cover. Carefully, remove the cover to reveal the battery. Unplug the battery connection and replace with the new battery. Replace the plastic cover and the ear pad.
Check battery wires
Check the wires leading to the battery. If one is shorted out, use the steps listed above to replace the battery.
Headphones will not go into pairing mode
The headphones do not indicate they are ready to be paired.
Prior Bluetooth connection
Make sure no other devices are connected before trying to pair.
Switch the headphones off and hold the power button for 4-5 seconds.