So there is this silent squeeking sound from the Mac when it's sleeping. It's defnitely not the fan. I can only hear it when I put my ear to it, it's very silent, but I don't like it. I googled it, and I see other people getting this even after the replacement. The interesting part is when Mac is on, there is NO sound like that, I can only hear the fan, but no squeeking. Also, I can hear a very silent electric prrrr sound when it is off, but plugged in. These things common and normal?