Err 80 appears when I turn on my Canon EOS 5D Mark II

I had to take mine to a Canon service center as none of the methods suggested online (switch off, remove battery/lens, insert battery/lens, switch on) made the error code go away. I got the repair covered by manufacturer's warranty. Apparently Error 80 is a somewhat typical error code for this camera model.

I've just got my camera back from repair and this was apparently caused by water damage to the DC-DC board, an expensive repair but I hope that my camera will now work well for some time to come! I've not yet worked out how the water got in - but I'm suspecting a damp camera bag after a seaside shoot.

Just wanted to add to this thread in case my solution can help anyone else.

I just had a similar issue, occasionally got an Error 80 when powering up. I would get no display with any of my cards in, but if I took the card out my display would start up again, but obviously I couldn't take any photos. As soon as I put a card in, the display wouldn't work anymore, and the camera would focus but not fire.

Tried removing the batteries and leaving as well, which only temporary cleared the error message (but the issue remained).

THE SOLUTION Sent a message to Canon and their recommendation was: Turn off camera, remove batteries and compact flash, close all doors. Turn camera back on, and hold the shutter down for 30 seconds. Turn camera off, put batter and compact flash back in, and turn on.

Everything works as normal after that. Hope this helps!

To make things a little more clear you can see this tiny screw when the rubber covers for USB and MIC are removed. It is the screw slightly left of center inside below the rubber covers. The battery slips out easily using a large screw driver on the bottom of the camera to push or twist the notch for the slide tray which is located on the bottom of the camera. There is an arrow indicating which way to push.

I have the Mark III and I just get a flashing Error code 80. When this happens nothing works. Turning it off and back on does not help. Removing the battery takes care of the problem.

I still am unhappy about this. I have a card in the camera even though I never use it. I'll try removing that and see if it makes a difference.

Blow some compressed air into the memory card slot, mostly it happens because of dust inside the memory slot. I hope it will work for you guys :) all the best!!

I understand this is an old thread, but I’ve had similar issues and I wanted to note down my solution for anyone looking in the future.

My camera functioned fine without a CF card. Would take pictures perfectly and you’d just get a “No Card” message. When the CF cards was used, I got an Err 80 message.

From the above comments, I misdiagnosed the issue thinking the fault was internal to the DC DC board. However, it turns out that one of the pins of the CF card holder was completely mangled.

Stripping the camera to the main board and reattaching the pin worked.

Hope this may help!