to the Pros (have you seen this)

[spedmetal]

The LA chip has nothing to do with what laser goes in what unit. The LA chips are in both the KHS-400C units and the HD7 units.

If you got an HD7 laser to work in a unit that originaly had a KHS-400C (or vice versa ) it will work but not well. The KHS-400C will act wacky before it finally starts to read the disc. You will hear loud clicks from the laser trying to focus and it will take a good 30 seconds before it will boot and it will sit at the browser screen while its doing this. Using a KHS-400C in a unit that has a HD7 in it will also wear out the KHS-400C very quickly because of the hard time it has focusing in the beginning of the boot process.]

Partial replacement as in you leave the dead LA in and attach the "partial" replacement. The other 2 I linked to you replace the whole LA.