The problem usually occurs when the Encoder strip a think plastic strip falls out of its guide inside the printer. Here is how to fix it:
- Lift scanner cover and remove the two plastic panels covering wires. Mark down position of cables then remove them, and remove the now-freed top scanner section entirely
- Remove screws from top plastic shell (There’s two in the back and four in the front, there’s also two plastic tabs in the front that must be bent aside before you can remove the top shell.)
- Gently put the encoder strip back in its plastic guide.
- Restart Printer