Modders don't want to buy a complete power supply to test out Slims. Instead of having 2 PHAT power supplies, just just your normal power supply and then plug in the adapter when you want to test out a slim. Cheaper, cleaner, and easier.
You should replace your laser lens if your system has the following problems:
Economy BIOS Clip Testing Unit ! Economy BIOS Clip Testing Unit is a very useful assistant for Mod Chips with BIOS clip installers. It displays the result of the clip installation and connection by LED signal!