General Printer Troubleshooting:

• Make sure the printer has power and is on-line. If you are using a manual printer sharing device, make sure the switch is set to activate the correct printer.
  
• Turn it off and on again to reinitialize any internal settings that may have gone astray.
  
• Ensure that the tape that seals the cartridge ink port is removed prior to installing the cartridge.
  
• Use the printer's own self-test, according to the manufacturer's recommendation. If it fails, you have verified that the problem is within the printer. If the print head is not moving at all, the transport motor may have failed.
  
• If the printer that you are using is not set as the default printer in Windows or the printer driver is not installed, the printer may print garbled characters. You may also receive errors when you attempt to print from applications.
  
• If the printer passes the self-test, try a test print using the Print Screen capability within DOS. If the Print Screen fails, you know the problem is in the relationship between the printer and the computer. Inspect the cable and the cable connections. Replacing the cable with a known good cable is worth trying since cables are so frequently the source of printer problems. Cables can fail with broken wires, loose or broken pins, or incorrect pin-outs.
  
• If the printer is connected to the computer through an add-in device, remove the add-in device and connect the parallel cable to the printer and then directly to the port on the back of the computer.  Some examples of add-in devices are: switchboxes, parallel port scanners, external disk drives, external tape drives, security lock keys, or external CD-ROM drives. Some add-in devices may interfere with proper communications with the printer. Try printing again. If the printer prints successfully, the cable may not have been connected properly, or the add-in device may have been interrupting communication with the printer.
  
• If the combined length of the cables connecting the add-in device and the printer exceeds 10 feet, communication can also be disrupted. In addition, the software that controls some add-in devices may take control of the printer port interfering with any other device attempting to use the same port. In some cases, the software for the add-in device should be disabled or uninstalled. Remove any add-in devices and uninstall the software for those devices, then try printing again.
  
• The message "out of paper" is sometimes erroneously reported when there is plenty of paper, and can indicate a physical problem with the printer.
  
• If the printer port is not properly identified in CMOS, the printer may not function properly and you may receive errors when trying to print. Check your User’s Guide on how to enter CMOS. Once in the Setup utility, locate the LPT1 settings. The address setting for the LPT1 port should be 3BCh or 378h depending on what kind of video card you have. The IRQ setting for the port should be 7 and LPT1 should be enabled in order for the printer to print correctly.
  
• If the Print Screen succeeds, the problem may be with your application or its configuration. For example, your application may be set up to direct output to a file instead of the printer, or you might be directing the output to the wrong communications port.
  
• Try connecting a different printer to this computer or try connecting the printer to a different computer and print a test page. If this printer works when connected to another computer, there may be a problem with the port on your PC. If this printer does not work when connected to another computer, there may be a physical problem with the printer.

• Poor communication between the printer and the computer may cause garbled printing or printer error messages. This may be caused by incorrect parallel port configuration in the computer setup utility. Below is a list of some of the common parallel port settings with a brief explanation for each:

  >NOTE: For information on checking or changing the parallel port configuration, see the computer documentation or contact the computer manufacturer.
  

• ECP ECP stands for Extended Capabilities Port. This setting allows the computer parallel port to send and receive data in both directions simultaneously. This is the preferred and the fastest type of communication available to printers. It is the preferred parallel port setting for most HP DeskJet printers.
  
  
• SPP, output, compatible, standard, or Centronics These settings allow the parallel port to operate in an output-only mode where data can be sent out to the printer. In this mode, the parallel port can also receive limited feedback from the printer. These can be alternate port settings for HP DeskJet printers if the ECP port setting is not available.
  
  
• Standard bidi, bidi, or bi-directional These settings allow the computer parallel port to send and receive data but only in one direction at a time.

 Troubleshooting Laser Printers:

• Be sure all dip switches are properly set for your configuration. Laser configuration is sometimes done by a control panel of buttons with an LED display that permits you to alter configuration memory. Be sure that the application being used is properly configured for the printer as set up.
  
• Fuzzy laser output could mean you have a dirty corona wire or you are running out of toner. Horizontal lines or splotches indicate possible damaged or dirty print drums or rollers. Since some of these components are part of the cartridge, a useful quick fix is simply to change the cartridge.
• If laser images seem disproportionately long or short, the drive motor may not be moving the paper through at the correct speed.
  
• Failure of a laser printer to go on-line might be a communication interface problem. It could also indicate a faulty control panel. Try powering up the printer with the cable removed. If it now goes to "ONLINE" (or "READY"), suspect the cable or its connector.
  
• If you are printing totally black pages, suspect a broken or fouled corona wire. If that is not the case, replace the toner cartridge.
  
• If the print appears speckled, it is probably the fault of the primary corona grid which is part of the toner cartridge. Replace the toner cartridge.
  
• If white streaks appear in your printing, shake the toner cartridge to insure an equal distribution of powder. If that doesn't work, clean the transfer corona assembly. Contamination on the assembly will prevent it from holding the electrical charge needed to attract toner from the drum.
  
• A repetitive pattern of printing defects, such as an identical smudge every 2 inches may indicate a defective fusing roller. Try cleaning it according to your hardware vendor's instructions. If that does not work, you may need to replace the fusing roller assembly.

• If the printer self-tests OK but will not print jobs from the computer, check the following:
  
  • Dip switch settings
  • Proper driver for your application software
  • Bad or disconnected cable
    
• Some printers have both serial and parallel connections. If one doesn't work, change cables and try the other. Be sure to change any dip switch settings needed by the printer to acknowledge the change. If this works, you may have had a physical problem with the output port on the computer or the input port of the printer that you tried the first time.
  
• If a dot matrix printer shuts down and recovers frequently, it may be having problems with its "thermistor". A thermistor is a device used to keep the printer from overheating. Try replacing this part before you replace the entire print head.
  
• Some printers can be set by dip switches for unidirectional or bi-directional printing. Bi-directional is normally faster, but might cause problems with graphic output for some combinations of applications and printers. If you suspect this problem, reset your dip switches for unidirectional printing.
  
• If your output is double-spaced when you expect single-spaced, you may be getting an extra Carriage Return and Line Feed at the end of every line. Reset the dip switch(es) controlling this.
  
• If your print quality is poor, first check the ribbon for wear. Also examine the print head spacing. Your head may be too far away from the platen for your current paper thickness. If adjusting the spacing doesn't solve the problem, clean the print head itself with a cotton swab dipped lightly in alcohol.

Troubleshooting Network-Related Printer Problems:

• If a network printer sometimes goes off-line for no apparent reason and works fine when it is reinitialized, you may have a static problem. Large amounts of static can be generated by certain special papers, such as carbonless forms. Make sure your printer is properly grounded.
  
• Plotters need to function much as printers in order to accept a job to plot, but plotters can have no direct interaction between themselves and the application.
  For example, the AutoCAD application talks directly to a COM port, then waits for a reply from that port. Since NetWare® software only redirects printing to LPT ports, AutoCAD ends up waiting for COM port activity when there won't be any.
  You can handle this problem by saving a print job to a file and then using NPRINT or PCONSOLE to print the job. An alternative would be to plot to a file named "LPT1" after capturing the device LPT1 with the CAPTURE command.