First we'll open up 2-XL's enclosure - be sure to disconnect power and remove any cassette before starting. Remove the 12 screws on the back, put them aside for later use, then carefully open the enclosure.
To accommodate our new functionality, we'll need to remove 2-XL's 8-track cassette player and button assembly. Desolder its wire connections, remove any screws and slide the carriage and button assembly out of the enclosure.
The original LED eyes are dim compared to common 3mm LEDs available today, so we'll give them an upgrade as well. Desolder the wires connected to the eyes and then unscrew and remove the face plate.
Finally, desolder the remaining wires connected to the power jack and volume potentiometer. We'll wire power for the Metro to through these points later on.