Voltage yes but the capacity to power it may be shot. Only reason I am suggesting replacing it is I saw a post on the internet where that alone solved an Error 40 problem and it is a cheap option also.
I have had my Eos 7d Mk1 for a while now and recently had a problem. In photo mode when using the eyepiece the mirror freezes when taking a photo after the first or second shot, I can take photos fine in video mode or when I'm using the screen to preview my shot, I've tested my two lenses, Ultrasonic 50mm and Ultrasonic 28-135mm and it freezes with both, I've formated the card and reset settings, don't have a battery grip, and shoot primarily manual, although this seems to effect all modes. I know the camera is getting old and has been used 2-3+ times a week for over two years now. If there is anything else that would help I'll do what I can, thanks!
nothing on the screen as it isn't on when I'm taking the photo, through the eyepiece it just goes black, including the displays
12/05/2023: New firmware updates are available.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.