We got a Soundcraft SI3 Expression about 3 weeks ago. Everything has been going fine, till today - all of the sudden, the TRIM does not do anything. If you adjust the faders up or down, we get volume change, but if you turn the TRIM, nothing changes. I have the TRIM all of the way up and the fader all the way up - the mic should be SCREAMING, but it isn't. What is happening? I have rebooted, checked cables, etc. Nothing works. I don't know what happened - everything was fine 3 days ago. HELP!!!