A common problem with the Philip's CD-I Roller Controller is that the IR Emitters will degrade in performance and the track ball with stop tracking. The buttons will work but the trackball won't move. This can be fixed by removing and replacing the 4 IR Emitters.

You will need:

Basic soldering skills
Solder / Soldering Iron
Solder Sucker / Solder Wick
Wire Snips
4 x Side looking IR Emitters - My local electronics only had these OPB815 which I took apart and removed the IR emitter (shown in steps). Digikey sells these LTE-302's that should work.
Standard Philips and small Flat Head screwdriver

Step 1: Start by Opening Up the Roller Controller

Remove the 5 standard philips screws on back.

Slowly remove the top of the controller and detach the plug from J3 so the top can be fully removed.

Mark J2 so you know where to plug it back in (J2 has the green wire in the plug) then remove the wires from J1 and J2.

Remove the ball.

NOTE: Click on individual pics throughout the steps for full sized pics with annotations.

Step 2: Remove PCB

Remove the remaining 6 philips screws, two holding the PCB and 4 holding the black mounting bracket.

To remove the PCB you only need to remove the right ball roller guide. Use a flathead screwdriver to come up from underneath and pop off the top retaining clip (see pic notes).

You can now carefully slide the PCB up and remove it (see pic notes).

Step 3: (OPTIONAL) Remove IR Emitter From Assembly

If you purchased 4 of the IR Opto's I linked in step one then you will need to remove the IR emitters from them. If you purchased from digikey you don't need to do this.

I used a small flathead screwdriver to break apart the opto holder and remove the IR emitter - see pics.

Step 4: Remove IR Emitters

You only need to desolder the Ir emitters - you do not need to remove the entire opto assembly.

Desolder and slide out the old IR emitters. If you properly remove the solder from the PCB the emitters should easily slide up and out of the housing - I used a small flathead screwdriver to push up on the pins from the underside and the slid right out.

See pics for details.

Step 5: Replace IR Emitters

The new emitters may be a little harder to slide in - I lined up the back of the emitter using a flat head and pushed it in so that the 'bulb' popped in after the lower backside of the emitter. It didn't take too much force - I then used a flathead to push them down flush and even.

Solder them back in place, clip off the ends, then put the PCB back into the unit by reversing early instructions.

You can test the stick out before screwing everything together by attaching J1, J2 and J3 and using your fingers to move the ball rollers.

Once its all working put all 11 screws back in (6 on the inside, 5 on the outside case).

Enjoy your working Roller Controller!