ps3 super slim disc read issue

Hi i have an issue with a friends ps3 super slim. It is failing to read the disc. DIsc spins for a short period. Laser move. Icon shows on the top right of screen but it is failing to read the disc. Is this purely down to a laser replacement. I have cleaned it to make sure there is no dust etc on laser heads but i am worried if i replace laser it could be an issue elsewhere. What are the symptons of the controller chip failing.