Take a note of the pin connections
Ensure there no disc in the machine, remove the parallel
port cover on the back, flip your machine over and remove the 6 retaining screws 
Flip your machine back the right way and lift off the top cover, remove the drive unit by gently pulling out the
ribbon cable and the small motor supply plug, lift the drive unit clear and set it in a safe place
Disconnect the second ribbon cable and the power supply cable, remove
the three phillips screws holding the plate and lift it clear, you might have to wiggle it a bit as it tends to hang on the locating pins
Remove the 5 phillips screws holding the system board in place and lift the board clear
This is the system board removed and the screening folded back for access
Here's a close up of the solder points where the mod-chip will be fitted, you can use a glue gun or double sided tape to secure the mod-chip
in the area marked, a small piece of tape keeps the wires from flopping around
