Check the output pin. If it reads 0V or significantly below 3.3V, the regulator chip is blown or a decoupling capacitor is shorted directly to ground. Repairing Trashed Solder Pads
The definitive historical archive for controller engineering. Users have mapped out highly detailed, color-coded trace diagrams for Matrix, CG, and CG2 boards. Xbox 360 Controller Schematic Pdf
The Ultimate Guide to Xbox 360 Controller Schematic PDFs: Repair, Modding, and Mapping Check the output pin