No sound unless channel is selected by the fx selector

My XDJ-XZ has suddenly developed a sound issue. I use the controller in standalone mode with USB.

No sound comes from any channel unless the FX selector is set to that channel.

For example, if I select channel 1 on the FX selector, that channel will play. If I select channel 2, that channel will play.

I have always used booth speakers with my controller, but the booth level no longer controls the volume.

Any ideas what would cause these issues?