Yamaha RX-V4ABL User Manual page 256

TROUBLESHOOTING > When any problem appears
The front display is turned off
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The brightness of the front display is set to be turned off.
Set "Dimmer" in the "Front Display" menu or "Setup" menu to bigger than "-5". For details, see the
following:
"Adjusting the brightness of the front display" (p.200)
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