Hi Carlos, I recommend that you check the fuser outside the printer, entering a sheet and pulling the pressure roller gear by hand, if the sheet is going well, install the fuser and check: that the paper passage sensor (is behind the pick up) operates when a sheet passes and returns to the initial position, it is necessary to disassemble even the back plate that covers the plate with the optocoupler sensor, the sensor has a flag that is activated when the leaf passes, and it has a spring that places it in the initial position (normal closed) when it finishes passing the leaf. Figure of the position of the paper step sensors: Also check the solenoid and the pick up gear, you have to disassemble the side, you will find a solenoid like the figure: the damping rubber of the activator plate degrades and the plate is stuck, it is a very common problem, Not only the fuser can cause the paper lock, the complete mechanism of paper taking, pick up, separation, solenoid, gear can be the cause, the controller senses the time from the take (first turn of the pick up until the exit of the fuser, if the times are altered by these parts, the controller stops the process and the blade is in any position without completing the cycle. I await your comment and experience, best regards