Check the rear-panel fuse holder. If the internal filament is broken, replace it with a fuse of the exact same amperage and voltage rating. No Sound / Protect LED is On
Balanced or unbalanced connections providing flexibility for various mixers, preamps, or audio interfaces. 2. Audio Outputs gear one pa2400 user manual
Ensure speakers are connected correctly, the Master volume is turned up, and channels are not set to "zero". Check the rear-panel fuse holder