Went to use Ch 09 and Ch 10 with mics today.  They seem dead. Both have lots of noise floor. Ch 09 will pass 48v and receive signal from mic, but has lots of background noise.  Ch 10 takes no input and only has the noise.  With nothing connected and preamps set to the same gain, you can see the line noise in comparison to Ch 11.

https://www.dropbox.com/s/zlp1g78aoihlr … roblem.png

Thoughts?  Why?  If not able to fix with a reset, what is the repair process like for these units (in USA).