By A Mystery Man Writer
If your date and time battery needs to be replaced, follow this guide to replace it. The required date and time battery is a CR2016 lithium.
Canon EOS 40D - iFixit
Canon Knowledge Base - How to replace the date/time battery on the
Canon DSLR - iFixit
Nikon D3500 vs. Canon T7: Which is better?: Digital Photography Review
Canon DSLR - iFixit
Nikon D3500 vs. Canon T7: Which is better?: Digital Photography Review
CANON EOS40D DS126171
Canon Camera Repair - iFixit
Canon EOS 40D Shutter Assembly Replacement - iFixit Repair Guide
Canon DSLR - iFixit
Canon Support for EOS 40D