Resposta para "Why won't my 5D Mk II turn on?"Usually, there are some pcbs underneath the small lcd display, that contain some very small SMD fuses. Fore some reason - bad battery, bad card, power spike, they get blown, and then no power to camera. I already fix a 5D classic having an identical problem. All you need is skill, a set of screwdrivers, multimeter, SMD fuse and soldering iron or station.