I did what you said, disconnect and reconnect the display data cable but the problem didn't go away. Any idea how to fix this?
For my mid-2010 mbp, removing the 4mm screw is not enough as the camera cable bracket is under the black cover. I need to unscrew another screw (see the dark cover in step 6). However, the speaker (dark circle in step 6) is a strong magnet and the little screw flew onto it and crack the speaker slightly. You need to be very careful of this. The sound wasn't as clear when I turn on loud volume after that.
I didn't have to do step 4 for my mid-2010 13" mbp.