Yamaha AVENTAGE RX-A550 Owner's Manual page 96

Problem
The unit cannot be controlled using the remote
control.
Cannot select the desired input source even if
"INPUT" is pressed.
The RED/GREEN/YELLOW/BLUE keys of the
remote control do not operate.
Cause
The unit is out of the operating range.
The batteries are weak.
The unit's remote control sensor is exposed to direct sunlight or
strong lighting.
The remote control IDs of the unit and the remote control are not
identical.
The function which skips some input sources is set.
The device which is connected to the unit via HDMI does not
support the operation of the RED/GREEN/YELLOW/BLUE keys.
The settings of the RED/GREEN/YELLOW/BLUE keys of the unit's
remote control have been changed.
Remedy
Use the remote control within the operating range (p.4).
Replace with new batteries.
Adjust the lighting angle, or reposition the unit.
Change the remote control ID of the unit or the remote control (p.90).
Set "Input Skip" of the desired input source in the "Setup" menu to "Off" (p.83).
Use a device which supports the operation of the RED/GREEN/YELLOW/BLUE
keys.
Set the "Remote Color Key" settings in the "Setup" menu to "Default" (p.84).
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