No. If the fat PS3 has a Single Laser (KEM-400/KES-400) then it will not be compatible with the PS3 Slim because the Slim has Dual Lasers. And the BD drive is a bit smaller than the fat PS3. Just buy a Replacement drive. I think the Slim's Blu-Ray laser model is KES-450.
I have a issue with mine also I dont get why my slim will play all games,dvd,etc but wont play certain blurays. It plays Tron legacy on bluray but not Independance day. Now my Fat ps3 plays both? Is it because the fat ps3 is older along with Independance day or not ? Im just trying to figure this out :wtf: