This is a direct replacement for the factory power LED in your Commodore 64 breadbin computer.  The LED clips into the factory location once you've removed the original LED.  This is completely reversible if you'd like to eventually go back to the original LED.

How it works is when the CPU generates an IRQ the green LED lights up, otherwise is red, if the IRQ is turned on and off quickly the led is orange.

The small board connects to three points on the back of the cartridge connector inside the case using IC clip connectors.  It connects as shown in the photos to +5V, GND and IRQ.  Instructions are provided with the item when purchased.

Note: IC clips and wire colors may not be the same as pictured.  Wires will be marked accordingly.