Replace the Internal Scroll Wheel Micro-switch

Safety Warning: This procedure requires soldering and will void your manufacturer warranty. If your device is still under warranty, contact Logitech Support for an RMA instead of proceeding.

Tools Required: Phillips head screwdriver, thin prying tool, soldering iron, desoldering pump or wick, lead-free solder, and a replacement micro-switch (typically a 3-pin tactile switch compatible with the G403 assembly).

Steps:

1. Remove the mouse feet (skates) carefully using a thin prying tool to expose the hidden mounting screws underneath.
2. Unscrew the chassis fasteners and gently separate the top shell from the base to expose the internal PCB.
3. Locate the scroll wheel assembly and identify the specific micro-switch responsible for the middle click.
4. Use a soldering iron and desoldering tool to remove the old, worn-out micro-switch from the PCB.
5. Position the new micro-switch into the mounting holes and solder the pins to the PCB, ensuring a clean connection without bridging.
6. Reassemble the mouse shell and replace the screws.
7. Apply new adhesive mouse feet to the base.

Verification: Plug the mouse into your computer and use a browser-based mouse testing utility to confirm that the middle-click registers consistently on every press without intermittent failures.