My almost 3-year-old ACD started emitting an annoying humming noise about half a year ago when I made a raid0 array out of my two 256 GB SSDs in my 2010 Mac mini. Because the Mac mini was placed by the side of the ACD and connected to it, I originally thought that the humming noise was from the two SSDs in the Mac mini without checking carefully.
When I replaced the two 256 GB SSDs with a single faster SSD of 512 GB, I accidentally discovered that the noise was actually from the ACD!
What surprised me is that, when I unplugged the ACD from the power strip for a day, the noise was gone when I plugged the ACD to the power strip and turned on the Mac mini. I suspect that the noise may come back once the ACD gets hot!
My questions are:
(1) What actually caused the humming noise from the ACD?
(2) Why could the noise be suppressed by unplugging the ACD from the power strip for a period of time?
When I replaced the two 256 GB SSDs with a single faster SSD of 512 GB, I accidentally discovered that the noise was actually from the ACD!
What surprised me is that, when I unplugged the ACD from the power strip for a day, the noise was gone when I plugged the ACD to the power strip and turned on the Mac mini. I suspect that the noise may come back once the ACD gets hot!
My questions are:
(1) What actually caused the humming noise from the ACD?
(2) Why could the noise be suppressed by unplugging the ACD from the power strip for a period of time?