Odd nF4 Audio Problem

[macprodan]

audio out keeps switching, normally i have audio coming out of the Green port on the Back Front Left and Right... but today no sound out of logic unless i plug into Black output Port Rear Left and Right, then closed logic opened garageband and no audio unless i plug into the orange port..

 

this is driving me mad already try a reeboot and the same prob..

 

any way i can use the spdif out on nf4 instead.. perhaps that will sort this mess.