1. Remove your warranty sticker, located next to the power cord. Take off the cover to the expansion bay.
2. Remove the screw covers on the very bottom of your playstation 2. There are six total. Four of them will be rubberized and two will be plastic. You may need a flat head screwdriver to remove the plastic ones. Ignore the extra 4 plastic covers on the raised, upper portion of the underside of your PS2, these are for removing the top shell.
3. With a phillips-head screwdriver remove the six screws under the covers you just took off. Four short and two long.4. Pull up on the bottom portion of the case to remove it.
5. Remove the metal shield covering the circuit board (the shiny one). With the front of the PS2 facing toward you, it is on the right. There is only one screw holding it in place.
6. Remove the expansion bay plate (the dull one with holes). With the front of the PS2 facing toward you, it will be on your left. Once again there is only one screw holding it in place.
If you still get disc read errors after about 20 degrees of rotation, put the screw back to the 12 o'clock position and start moving the screw clockwise two degrees at a time.It may take a while, but you will most likely find the sweet spot where your discs begin to read again. I have never had to move the screw more than 30 degrees, although I have heard as much as 180 degrees are needed for a modded PS2 to play backup CD-Rs.
12. Try a few different trouble discs before re-assembly to make sure you dont need more fine adjustment. As well, hold the PS2 elevated in the horizontal position and make sure it reads while in this position. I have found that slightly more voltage (2-6 degrees) is needed to run discs in the horizontal position than the vertical position.
13. Turn off the PS2 and re-assemble it.