Ok, so I replace the disc reader on another identical unit and it's ok, so the problem resides on the logicboard, i have been taking readings with the multimeter, the problem is that the motor that moves the laser unit back and forward through the disc is not moving at all, so i'm trying to find the bad chip that is not passing the righ voltage to that motor from the logicboard, the service manual doesnt include schematics just pics of the board circuit prints