Take a look toward the top of figure 1, which is the inside of the back of the guitar neck. The ‘bottom’ of the printed circuit board is now visible, held in place with two screws, one at each end, and a ribbon cable that attaches the board to a connector at the guitar-end of the neck. For this guitar (World Tour), there are 8-10 T-10 torx screws holding it together. In figure 1, the back of the guitar neck has been removed. To see the way the fret buttons ship from the factory, we need to open up the neck of the guitar.
What do the existing fret buttons look like? There are the bare minimum of moving parts and zero alignment/assembly issues. This approach of using a flexible membrane and conductive pads is a super inexpensive method of making thousands-and-thousands (millions even?) of products that work well and are easily mass produced. When a fret is pressed down, the membrane deforms, allowing the pads on the membrane to contact the mating pads on the printed circuit board, and the electronics are able to register the keypress. This all sits on top of a small printed circuit board that has matching conductive traces that align with the conductive pads on the silicon membrane. The membrane contains two conductive electrical pads. On a standard Guitar Hero type guitar, the fret buttons (red, green, yellow, blue, orange) sit above a silicon membrane. Guitar Hero Mechanical Fret Button Upgrades What’s the deal with the existing fret buttons?