I just got back from three days in camping, and brought my 7D with me. On our way out of the woods, I turned the camera on, and heard a the mirror popup, as when the camera goes into live view or video. It turned out that the camera was in video mode, and did not want to leave it, I figured something was wrong with the live view/video switch, and hoped that it would go fix itself.


The next day, it worked a little better, but it was still flaky. Still/video switch was not reliable -- it would go into video mode, but not come out, when I turned the selector. After waiting a while, I figured the camera was damaged -- most likely from my sweat that had been dripping on back while it was hanging around my neck.


Seeing as it was out of warrantee, I figured that there was an electro-mechanical problem with the switch, so I decided to perform surgery. After removing both batteries, I went at my precious with a screwdriver. I was able to remove the back of the camera by unscrewing three screws at the bottom, four around the viewfinder, and one hidden under the adhesive cushion. After that, the back came off easily, and one ribbon cable connected the back with the rest of the camera. A few more screws, and RF shield behind the dial, joystick and video switch was out, and innards of the video switch were exposed. Sure enough, the circuit board and the little pieces of sheet metal that made up the switch had some corrosion on them, which I was able to clean off with some Eclipse lens cleaning solution (e.g. methyl alcohol) (don't know if that was the best thing to use, but I figured it was less corrosive than water, and evaporates faster.)


I took me a couple attempts to reassemble the camera and get all the rear controls working again -- first time, the video switch needed more cleaning, second time, the rubber piece at the center of the rear control dial was left out, and thus thus the set button did not work. Third time, the lock switch on the bottom of the rear dial was not working (actually is was always locked), and the forth time, I has a good as new camera, for 1-1/2 hours of labor. Sorry I didn't take any pictures of the repair. I was too focused on getting the camera working again.


Lessons learned:


1. While the controls on the right side on the 7D (the LV/Video switch, joystick, and control dial) are not weather sealed, they are located far away from any sensitive electronics, so a switch may fail, but it is likely that the contamination will not make it past the switch. I don't know if Canon sells the parts for those switches (small pieces of sheet metal and tiny circuit boards), but if they do just about any damage to that area should be easily repairable. Even without parts, you can probably clean the contacts and get things working again.


2. I need to protect me camera from sweat dripping off my body. I have a Keyhole harness, and absolutely love it, but that does keep the camera on the neckstrap facing down. I need rig up a piece of cloth or plastic to the harness to cover the camera, and protect it from any drips that may come off of me.


I will need to come up with some solution to protect my 7D from my sweat when I'm hiking. I use a camera harness which keeps the camera in the same position as if I were wearing the neck strap (which I was), but transfers much of the camera's weight to my backpack. The camera is facing down, and most of its weight is on the harness. This harness works great, and keeps the camera where it can quickly be accessed.