Repair Parts Mouse Encoder Wheel Board For Logitech G603 Mouse Wheel Board - Mice & Keyboards Accessories - AliExpress
A different kind of scroll wheel problem G603 : r/LogitechG
Logitech G603 Lightspeed Wireless Gaming Mouse : Logitech G603/G613 wireless gaming mouse and keyboard review: Is it possible to game without wires? - HardwareZone.com.sg