DVD驱动器维修

I have a dell optiplex 740 and one day, it started not posting. It gave me error code 3 solid green. I figured out the problem. It was the dvd drive. The dvd drive is a sata. The model is GSA-H73N. It is by Hitachi-LG Data Storage inc. I want to try to fix it. Any ideas on what is wrong? dvd drive