I tried the same fix and found that the was a gap between the speaker connector and the thin film connector that is attached to the rear of the screen. I used some cotton wool balled up into a bud to close the gap and allow the connector to touch. Voila my old motorola now works again! Thank you for your valuable advice!
Craig M
March 2008
Try taking the four screws out of the main screen (you'll need a phone torque screw driver) and then cleaning the speaker and connection with switch cleaner or the like.
I had the same issue and switch cleaner worked for me. Cleaned with switch cleaner and left overnight so any residue had dried out. Worked perfectly the next morning.