HP LaserJet 4 Service Manual - Page 251

Table 7-7 Paper Jam Troubleshooting Checklist Jam Location Checks and Action Required Input Area Jams 1. Check that the Transfer Roller is fully seated and shows no (Sensed by PS1.) sign of wear. 2. Check that the Toner Cartridge is fully seated. 3. Check that the cassettes are not overfull and the media is loaded correctly. 4. Ensure that the media meets specs. (media is not too smooth or rough), and it has been stored properly. 5. Ensure that the paper tray is fully seated (especially if printing from the Lower Cassette). 6. Ensure that the spring force of the Lower Cassette is set correctly. Registration Area Jams (Sensed by PS1.) 1. If paper is damaged at the Registration Sensor (PS1), check that the Transfer Charge Roller is properly seated. Lower Cassette Paper Jams (Sensed by PS1.) 1. The LC Tray (Tray 3) is not fully seated into the printer. Seat the LC Tray firmly into the printer. 2. The Lower Cassette feed pressure (spring force) adjustment is incorrect. Set the spring force as shown in Chapter 3. Fuser Assembly Jams (Sensed by PS3.) 1. Check that the Fuser Pressure Roller Levers are down (LJ4 and 4 Plus Only). 2. Check that the Exit Sensor Arm (PS3) is free throughout its travel and that the Exit Sensor Arm is installed correctly. False Paper Jams 1. PS1, PS3, or PS5 are damaged or mechanically broken. 2. The sensor wires are damaged or disconnected. 3. The rear door is open. Paper Jam occurs when the last sheet of paper is fed from the tray. 4. Paper out sensors in the paper tray or envelope feeder may be defective, or the sensor flags may be broken or missing. PS2 is the sensor for the PC Tray (Tray 2), PS4 is the sensor for the MP Tray (Tray 1), PS6 is the sensor for the LC Tray (Tray 3), and PS7 is the sensor for the Envelope Feeder. Troubleshooting 7-21