HP LaserJet 4250 Service Manual - Page 382

Persistent jams If jams occur repeatedly, use the information in this section to diagnose the root cause of the problem. The tables in this section list possible causes and recommended solutions for jams in each area of the paper path. The information is listed in the order in which you conduct the investigation. In general, items at the beginning of the list are relatively minor repairs. Items at the end of the list are more significant repairs. Basic troubleshooting for persistent jams The basic troubleshooting process for jams consists of the following steps: 1 Gather data. 2 Identify the cause of the problem. 3 Fix the problem. Data collection To troubleshoot jams, gather the following information: ■ The exact error code that appears on the control panel ■ The location of the leading edge of all of the media that is in the paper path ■ The location of the media when the jam occurs: in the paper path or at the input tray ■ The timing of the jam: at power-up or while paper is moving ■ The location of any damage that occurs on the media and the location in the paper path where the damaged media stops ■ The relationship to a particular tray ■ The relationship to duplex printing ■ The relationship to the type of paper ■ The use of any non-HP supplies (non-HP supplies are known to cause jams) ■ Paper-handling conditions, including storage conditions, overloading trays, damaging media during loading, fanning of the paper ream, or use of paper that has already been fed through this printer, another printer, or a copier General paper-path troubleshooting Use the following information to isolate the cause of the problem. When you have identified the cause, use the tables that follow to find a recommended solution. ■ View or print the event log to determine if a particular jam error occurs more often than others. Try to identify a pattern. ■ View or print the event log to determine the frequency of a particular jam. If a jam occurs repeatedly at a particular page count, consider this event to be a single jam that the customer tried to clear. 368 7 Troubleshooting