We are aware of an issue -- most common with our pre-Raw Thrills cabinets -- where a cabinet's sound will fail entirely.
There are a couple of factors that can lead to this issue, but the Killer Queen Operator Menu has the fix that you need.
Open up the coin door on the Blue cabinet. If you look inside, you should see a pair of switches, with one having the option for "MENU." Press that switch to pull up the Operator Menu.
Due to varying hardware in our pre-Raw Thrills cabinets, the assigned Audio Device may differ from cabinet to cabinet -- that is to say, there is no Device Number that is "correct." Simply change the Audio Device until you hear a loud "ping" sound (you might want to turn the volume down on your cabinet before making this test; it's actually pretty loud sometimes.)
Once you have configured the correct audio device, exit the Operator Menu. Ensure that the change has stuck by opening the menu once more and double-checking that the Audio Device is the same as the one you just selected.
Enjoy the sweet sounds of Killer Queen.