[charlie_ps2]

A question asked on another forum about the function of the white cog led to some research by my famous 'mate round the corrner'. This is what we found.

This wheel adjusts the angle between the rails that the sled runs on and the disk itself. The rails should be parallel with the disk surface. When a new disk is inserted the laser does a process called 'focus search' where it moves the laser assembly up and down until the best (minimum spot size) is found. This is then used for the whole disk, but, if the rails are not truly parallel with the disk, focus will deteriorate as the laser moves away from the initial position (the inner most tracks). That is, the laser will be closer or further away from the disk at the outermost track positions and either is bad news.

So I can verify that the adjusting the white cog does have an effect and if it was set wrongly to begin with, by Sony, then you can improve things by adjusting it.

We tried with a machine that is in for a new laser assembly and got things very slightly better using this method, but not perfect. The new laser unit was fitted and behold, it worked first time without any tweaking.

So this is a 'fringe' adjustment; as the laser reaches the end of it's useful life, you MIGHT be able to squeeze some more life from it using this method.

The available adjustments therefore are:

Intensity (ohms/pot adjustment)
Azimuth
This method, let's call it Parallax.
Lens cleaning
Disk cleaning

This advice is provided at your risk.