Carefully clean the two copper contacts with cotton swabs and alcohol. After that clean with cotton swab and alcohol. Use a screwdriver and slightly scratch any oxidations off the surface of the lowest, protruding part of the silver contact. In particular the silver one that is closer to the back of the camera. Clean the battery contacts in the battery compartment. Step three: If the viewfinder is unusually dark, the camera gets no power whatsoever (the 7D uses polarizers for the viewfinder displays, such as the focus points to show up - these require a tiny amount of energy and if the power is gone for more than 4 seconds, the viewfinder will go dark - to test what I mean, remove battery, wait 4 seconds and look for yourself). Clean the main switch with a strong air blower while switching back and forth (sand!). Use screwdrivers to check the operation of the microswitches. If no: The camera receives power but will not turn on because either the main switch, the microswitch of the battery door, the microswitch of the CF card compartment, or several switches are not working.

Step two: Is the viewfinder unusually dark? Manual focussing seems off? If yes proceed to step three. If not (nothing at all showing on top LCD) proceed to step two. Is the battery symbol flashing? If yes, make sure your battery (including the Lithium battery) is charged, original, and new. Lithium battery fresh.ĭiagnosis step one: Look at the top LCD.

Canon 7d firmware history