Inside Logitech G903
Once we removed the screws and separated the top from the bottom of the mouse, the first thing that came to our attention was the battery, because we had to disconnect the cable to get here. It is a Li-Po with 750mAH at 3.7V. Considering the lack of space and weight added from this cell, to get twenty-four to thirty-two hours out of it is doing great.
While the top portion was still in our hands, we see Logitech opted to have the switches for the main buttons as part of the top assembly rather than connecting them to the main PCB below. In this instance, we see an Omron D2FC-F-K(50M) which is good for up to fifty-million clicks. There is a matching switch under the other main button as well, but it is installed with the markings in an area we cannot photograph.
The lower section of the mouse is where all the rest of the business happens, across three PCBs. At the heel of the mouse is where the battery plugs in, and the ribbon cable connects at the same end of the much larger PCB. Resting on top of that is the scroll wheel mechanism, which connects via the thin ribbon cable which is still connected.
The optical sensor used is the one specified earlier in the review and on the box. It is indeed a PixArt PMW3366DM-VWQU which has been soldered directly over the eye of the mouse.
The 32-bit ARM processor in charge of talking to the PC, controlling features and functionality, and is also where the profiles and settings are stored is made by ST Micro. We see no reasons why this STM32L100 should not be up to the task.
While most mice offer a scroll wheel that has a downward click, Logitech uses this rocker system, where the scroll wheel can be tilted left or right, delivering another pair of buttons to the mix. We also like the option of highly segmented movement of the wheel, or with the press of a button, free-wheel capability.
Once the G903 was reassembled, we plugged it into the PC, and allowed it to flash the LEDs in the center, but once settled, the Logitech G logo is the only thing that stays lit when wired. In wireless mode, the trio of lights in the middle are more active, but even then they shut down to save power for use, to extend the life of the battery charge.