Mackie mixer repair

[Guillermo 2012]

I have a mackie cfx 20 and suddenly only the moniters work I can't get any sound from the main speakers..I tested everything I'm sure it's the mixer what could it be?

 

[soundguruman]

plug the mains into the monitor speaker outputs.
Verify that the main speakers are working.
Locate the mackie repair center or a pro sound tech at a music store.
Probably an internal component failure.