The Sony PS3's serial number is located on the back of the PS3 system. It can also be located directly on the retail box of the PS3. When sending the PS3 out for repair, the PS3's serial number is your means of tracking the PS3 throughout its repair progress. Sony's official support centre has a section that allows you to enter in your PS3 serial number and it will tell you exactly where your PS3 is in the service process.
Go to the official Sony support website and agree to the terms of the repair agreement.
Click the button next to "Select your model number." Click the Sony PlayStation 3 model you have from the list that comes up. The model number is located on the Sony PS3 retail box.
Enter the serial number in the space directly below where you selected the PS3 model number.
Click the "Continue" button to track the progress of your PS3 service status. Once the PS3 is received by Sony, repairs take anywhere from one to three weeks.