I replaced my drum shaft bearing this morning and cleaned up the inside faceplate while I was at it, including the IBTS sensor. I reassembled everything and turned the machine on to make sure the new bearing was turning properly and heard this buzzing coming from the control panel. I turned off the roaster, waited a few minutes, and turned it back on. Same thing. Did I pinch a cable or something when reinstalling the faceplate?
That’s the IBTS fan. It should be normal. Check the RPM, but the sound seems normal to me.