The power supplies can be found on Ebay and from Canon. If
they're the same across many Pixma models, lots of people
seem to sell printers they got bundled with other machines
cheap.

Canon printers don't feature that heavily on eBay compared to others
and the power supplies differ by size and connections (some do 24 volt
and 5 or 7 volt output) depending on the model.

On testing this defective power supply just it blows its fuse - can
anyone advise on how to repair it? I fully understand that electronics
skills are required and I'm more than happy to spend the time and
learn what is necessary.

regards, Roy