However, if this tweak is of any use, the tvservice command will have to be added to Volumio again, because it's missing from the Volumio distribution. I'm afraid that don't have the expertise to do it!
Running 1.51, I looked for the command and it was on my system. And it worked as well with -s you get the status, -o turns it off (or --off) and you can turn it back on (-c) if you want. Just turned it off and let's see how it goes
Raspberry PI B+ with Hifiberry Digi+ (Audio-GD DAC) and NAD A/V receiver with Dali speakers