The potentiometer is located as shown in the picture. It's a very small cross-wing screw mounted on top of a little black box.

Now we need to adjust the potentiometer to make the optical lens laser stronger.

Using a very small flat head precision screwdriver turn the potentiometer no more than 3 degrees counter-clockwise.

Turning the potentiometer too much can result in the laser becoming too strong and actually burn the discs!

Turning the potentiometer clockwise would just result in a weaker laser and create even more DRE messages.