Last weekend I went to Downeast Maine (Lubec and Acadia NP plus a few hours on Campobello Island, New Brunswick), and my 7D was misbehaving again. Basically, the Live View/Video switch was not working, and as a result, the camera pretty much did not work. (Fortunately I only lost 1 day of shooting, and was able to repair it when I got back home.


My symptoms were the following: when I turn the camera on, I hear the mirror pop as the system automatically goes into live view mode. The shutter button does not work, but it is possible to cancel LV by moving the camer into C1 mode and back. I had similar problems before, most likely caused by sweat dripping off my forehead, and was able to fix it in the same way. This time I did not see as much salt on the circuit board, but I was in a very humid environment (lots of fog) for a few days, before I had any trouble.


This time, I took a few pictures of the repair process in the hope that it might help someone else in the same situation. This is the same repair I did before, but this time I have pictures. Sorry for the quality of the pictures they were taking with a Rebel XS, on-camera 430 ex, on the desk where I was working.


Tools: jewlers screwdriver set (flat and phillips head), notepad, toothbrush, cleaning solvent (I used Eclipse (pure methyl alcohol) since I had it -- I'm sure other things would work as well -- maybe even water, but I wanted something that would evaporate quickly to minimize additional damage to the camera.


First, remove both batteries from the camera and the eyecup, and the cover for the data connector on the bottom:








Next, map out the screws holding the back cover and remove them. There are 4 screws around the viewfinder, three on the bottom, and one hidden under adhesive thumb grip. The following picture shows the me removing that hidden screw








To insure that nothing gets lost, I mapped out the screws locations and places each screw in a circle indicating where it came from:





Now the back panel will come off:





The back is connected to the rest of the camera by a single ribbon cable. This can be removed gently prying it apart with a flat-head screwdriver:





Now the back panel is seperated:





My problem is with the LV/Video control which is to the left and next to the viewfinder (now that it is flipped). There is a single piece of metal covering the rear dial, the directional control (joystick) and the Live View/Video switch. I sketch out where the screws on that pies of metal are, and remove them





The little piece of metal on the notepad is the dial lock switch. That needs to be removed as well to access the controls. When the screw holding that is removed, the switch itself will fall out of the camera. It will need to be propped up when reassembling. (I used a folded piece of paper to hold it up.)


Speaking of that lock switch, it is connected to the piece we want to remove, so we gently pry it up.





Now the circuit board for the controls is accessible. Note that there is a bit of corrosion around to top button (e.g. LV/V) That gray plastic cover easily comes off, exposing the contacts on the board that make part of the switch.





Remove the cover on the LV/V switch and clean it with a toothbrush and cleaning solvent.








Then reverse the process and reassemble the camera.





-joe