TX-8470 When the unit is operating erratically

Try restarting the unit
Restarting this unit may solve the problem. Set the main unit to standby, then after waiting for 5 seconds or more, press and hold the ON/STANDBY button of the main unit for at least 5 seconds, and then restart the unit. (The settings on this unit are kept.) If the problem persists after restarting the unit, unplug and
plug the power cords or HDMI cable of this unit and connected devices.

Resetting the unit (this resets the unit settings to the default)

If the restart of the unit does not solve the problem, reset the unit, and restore all the settings to the factory default at the time of purchase. This may solve the problem. If the unit is reset, your settings are restored to the default values. Be sure to note down your setting contents before performing the following operations.

Note: that it is not possible to reset the unit during the Initial Setup
process. Before doing the following procedures, press RETURN to exit Initial
Setup.
1. While pressing and holding ZONE 2 button on the main unit with the unit turned on, press the ON/STANDBY button.
2. "Clear" is displayed on the display, and the unit returns to the standby state. Do not remove the power cord until "Clear" disappears from the display.