EOS 40D Won't Power Up

[robinkaspar]

I have a 40D I haven't used since I bought a 70D when it came out. The 40D has been stored in my bag in a closet without a battery, CF card, lens (body cap only), without anything that could render it useless. I brought it out of storage (not a hot attic, etc) in preparation to donate it to a worthy cause. It won't power up with the original Canon batteries (fully charged according to the original Canon charger). I bought 3rd party batteries which won't power it up. I bought a charger for those batteries and still the camera won't turn on. I can't think what else to try. My plan was to format all the CF cards I have and donate them along with the camera. It looks perfectly normal, the battery contacts look clean. What do I do with it? I don't want to invest any more money in it. 

[RLB]

I know this thread is old, but just want to add that I recently dug out my 40 D to give to my son-in-law and I had the same problem that it was described above. I checked all the switches in the CF door and the battery door and they were fine and did not solve the problem. Finally, I just turned the power switch all the way on and all the way off somewhat vigorously about 10 or 15 times then put the battery in and sure enough, it powered right up with the time and date reset screen. Put all that in and it’s been working great ever since!

Hope this helps somebody.