IPF 6400 unused for 1.5 years: not working after heads replacement

[onlyinnewfoundland]

Manual says 2836, 2835 codes mean unrecognized printhead. One for left, one for right. 280A is the same deal - something to do with unrecognized head mounted. 2010 is paper skew loading the paper or cutsheet so don't worry about that one.

Assuming the heads are genuine Canon, you've got a problem with your carriage relay board or the main controller.

Boards are expensive. Carriage relay, not too bad. I think on this machine due to size, you might have to replace entire carriage - not sure Canon sell the board by itself like they do on 44 and 60 inch variant.

If it's main controller, make sure you remove the heads first, replace board, update firmware and let it ask for printheads to be installed.

[ATB]

I work on these. Sitting for a year, ink has dried in the head(s),purge unit,ink tubes, and cap absorbers probably

Cap absorbers and heads done. how do I clean the purge unit and ink tubes?