While playing back a recording I have noticed a high pitched noise in my recording. Crap!! I just went over to record to see if it did that in while recording but the record button isn't lighting up! What is going on here?
My first notion for a high pitched sound is that you are getting feedback from another source. That happens to me once in a while when I forget to turn off the monitors while doing a project.
As for the other problem with the flashing lights, "I know nothing," as Sgt. Schultz would say.