Hi all, I am getting random (at least it seems random to me) buzz sounds coming from my 2009 2.66 Mac Pro that only lasts for a second. Some suggestions from the other threads recommend that I touch the case when it buzzes but by the time I reach for my MP the buzz stops. I've tighten all the screws in my sleds and pushed them so they are snug in the bay. Some have thought the buzz comes from the latch but my buzz sounds like it's from the front of the MP. A Mac Genius told me circuit boards can make a buzz sound from electricity going through it?? Others have said the buzz comes from the PSU (power supply unit). Where is the PSU in the MP? I haven't shaken my MP, which is one of the suggestions I read. I think it might be coming from the Super Drive. I took out the Super Drive for about a week and don't recall hearing any buzz sound. rgetter recommended re-aligning the ribbon cable (see quote of his post below), but how do you do this? I didn't see a ribbon cable when I took out the Super Drive. Any other reasons why my MP is randomly buzzing for a second? Otherwise all I hear is the peaceful hum of the fans.