Recently my AR8 mixer has started giving off a high frequency whine, which I assume is a coil whine, sometimes it can be really loud or be soft enough to be drowned out by everything else. Mixer still works perfectly fine otherwise; it's just really annoying. Have tried putting the mixer on a different circuit to see if that would eliminate the problem but nada. Is this something I, with no knowledge of electronics, can fix or send it off.