| Symptom | Possible Cause | Solution | | :--- | :--- | :--- | | | Dirty or worn rollers/plates; incorrect ink viscosity; pressure issues. | Clean rollers/plates, replace if necessary; adjust ink; calibrate pressure. | | Paper Jams | Obstruction in paper path; damaged/misaligned components. | Clear obstruction; inspect and repair paper path. | | Electrical Malfunctions | Power issues; blown fuses; circuit breaker trips; grounding problems. | Check power connections and grounding; consult electrical schematics. | | Registration Problems | Incorrect registration settings; faulty gripper bars/side guides/registration pins. | Adjust settings; inspect and repair mechanical components. | | False "Double Sheet" Detection | Sensor issues (e.g., with the Ryobi 500K); sensitivity resistor problems; power supply. | Check sensor alignment; clean the sensor; adjust sensitivity; verify power supply (25.6 VDC). | | Numbering/Perforation Unit Malfunctions | Issues specific to the NP unit; lack of manual. | Seek a dedicated NP unit manual or advice from forums for the 480K NP or 500K NP. |
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