The router uses fuses from the Cooper Bussman brand GMT series for the FPCs, MCSs, PCGs, and SFMs. The fuses are located in a fuse box on the rear of the midplane. When the fuse for a component blows, the component stops functioning even though it is installed correctly and the power supplies are providing power to the router. For more information, see Blown Fuse Indicators. For fuse replacement instructions, see Replacing a Fuse.