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. 

[Anonymous · Accepted solution]

Your camera has a date/time battery besides the camera battery. You could try replacing that battery. Your camera manual has the instructions on how to replace the date/time battery.

[robinkaspar]

Well, duh! Forgot all about this battery and no one else I've asked has mentioned it. Thanks so much Bob, I'm back in business.

[Anonymous]

Great to hear!

[MikeSowsun]

This makes no sense. Are you saying you just replaced the Date/Time battery and your camera now suddenly works? I also have a 40D and it functions very well with the Date/Time battery entirely removed from the camera. 

There must be some other reason why your camera would not turn on. 

[robinkaspar]

I wish I knew. But I replaced the date/time battery and inserted the other battery, fully charged, and the camera then powered up. So, it was the date/time by itself but the combination of the two. (I guess.)

[robinkaspar]

*wasn't"

[Anonymous]

I've heard of others having the date/time battery cause this issue on other Canon cameras.

[normadel]

This could be a case of a temperamental On/Off switch. On a (15-year) old camera, switch contacts can become corroded, even if it's just a light film on them. Repeatedly turning the camera on & off can wipe the film contacts clean. 

An application of an electronics contact cleaner may keep it working for another 15 years.

[shadowsports]

My guess.  The switch on the battery door might have been the cause.  🤔