When I adjust the volume on my RX-V473 receiver, the video signal blinks. Make sure that your HDMI input sources are all set to output at least 480p.
For cable boxes it would be listed under Videos Settings/SD Override. For more info, contact your cable box provider.
Blu-Ray/DVD players it would be listed under Video Settings/TV Settings/Type. For more info, contact your player's support line.
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