WARNING!!!!!

Removing the CMOS sensor, as shown above, will render your camera useless!! (no focus)

WHY?

This sensor (and many others) are very precisely tension-adjusted. It's called FBD or Flange-Back Distance. It's the distance between the lens mount surface and the actual surface of the CMOS sensor (below a low pass filter and below any sensor glass). Requires a special Canon tool to measure and adjust. There is a way around - you can use a high precision digital micrometer to measure it before removal and then adjust after putting it back in place. Still, high precision is required. Canon might refuse to work on your camera after you do it in a way illustrated above. I know at least a couple of such cases and one of them was related to this specific "repair guide". Please be careful!

Mike / camera repair tech