cartridges are static in this printer
You obviously have not seen an 837. I don't think you can help.
I have this manual, it lists corrective actions for common operational problems, then says to go to Epson site. It says \ to send it to an Epson repair center if recommended fixes fail.
I am aware of this route, guess I'll just bite the bullet and rip into it. I may end up wrecking it, but I'd have to get a new printer anyway.
This is an option if I can't fix it. thanks