I have a WF-3640. Error 0xF3 popped up upon turning the printer on 6 days ago. I have search forums for help and no result. I have installed new ink cartridges (not cheap) and a new maintenance box (also not cheap). Printer is 1 year 4 months old (out of warranty) and calling Epson support is no help. They say error is a "hardware problem" - dah! They will offer no help but sent me a repair code and a 15% discount if I buy a new printer. Please help - I have already invested over $60 trying to fix to no avail!.