Device will not power up when the power button is pressed.

Plug your device into the wall or a USB outlet. If it does not charge when connected to either of these, the battery or the charging port may need to be replaced. See Installing LG Vu CU920 Battery or Installing LG Vu CU920 Charging/Headphone Port.

If the screen remains dark, it is possible that the device is actually on, but the display is not working. Try powering up the device, waiting 30 seconds, and calling it. If the phone rings, it is possible that the screen is either disconnected or needs to be replaced. See Installing LG Vu CU920 LCD Screen

It is possible that the device is charging properly and the display works, but the power button does not work. In this case, the power button will need to be replaced.

If the device still won’t power on, the motherboard may need to be replaced. See Installing LG Vu CU920 Motherboard

During a call, the other person on the line cannot hear my voice

Check to make sure your microphone is not muted in the call.

If the microphone is not muted and the other person on the line cannot hear anything, it is likely that your microphone is malfunctioning. See Installing LG Vu CU920 Microphone

During a call, you cannot hear the other person’s voice

Check to make sure that the call volume is turned up on the device.

If the volume is turned up and you still cannot hear the other person in the call, the speaker may need to be replaced. See Installing LG Vu CU920 Speaker

The device fails to detect a headphone plugged into the headphone port.

Check to make sure the headphones are working properly by testing them on another device. Also try a different set of headphones on your device.

If the headphones are not the problem, the headphone port may need to be replaced. See Installing LG Vu CU920 Charging/Headphone Port.

The device’s display does not light up, and nothing shows up on the screen

Check to make sure that the battery is installed properly and is charged. If the display does not light up, the device may not be powering up, and the battery may be bad. If this is the case, check the “Device Won’t Turn On” section.

If the device powers up, but the display fails to light up, the LCD screen may be disconnected or need to be replaced. See Installing LG Vu CU920 LCD Screen.