Parts- Lasers and Sensors



I am interested in repairing the laser assemblies in CD players if at all possible. I have a basic understanding of the operation of the laser assembly, but would like to get specific data on the lasers and the detectors used in the assemblies. I am not sure what to call the detector that detects the light signal from the disk that detects the 1’s and 0’s . Where can I go to get data sheets on lasers and detectors? The assembly I am presently looking at appears to have a 3-Pin laser and a 10-Pin detector. However I am not really sure if the laser is the 10-Pin and the detector is the 3-Pin device.
I don’t know why a laser or detector would have more than 2 pins.
I am just starting out so any information would be helpful. The particular assembly I am looking at is from a Memorex Model No. MP3142 . I am interested in understanding what part of the system usually goes bad. From what I have learned thus far is that the usual cause of failure is a dirty lens, but in talking to others I have heard that the focusing lens gets beyond its limits ( either too close or too far away) where it can no longer focus on the CD.
I would like to be able to connect to the circuitry and and adjust whatever need to be adjusted, rather than just shooting in the dark without having any idea if what I am adjustig will help or not.
Some of the laser assemblies I have worked on use a motor to adjust the focusing lens , and some use a D’Arsonal movement to adjust the lens focus on the CD.