LED behavior during a cartridge change

This image shows the indicator lights before and after a cartridge is replaced.

On the plasma power supply:

1 (Yellow) When you set the torch-lock switch to the yellow lock (X) position while the plasma power supply is ON, the Torch Cap Light Emitting Diode (LED) on the front panel illuminates and a 0-50-2 code shows.
2 (Yellow) After you install the cartridge and set the torch-lock switch to the green "ready to fire" position, the Torch Cap LED extinguishes.
3 (Green) Hand torch: After the torch puts out the warning puffs of air, the 0-50-2 code extinguishes.