General Printer Troubleshooting:
WARNING: Some printers
differ from computers in that they do not have shielded power supplies. That
means that a plugged-in printer can expose you to full outlet power, which
is enough to kill you. Never open a printer case unless it is unplugged!
- 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
- 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.
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.
Troubleshooting Laser Printers:
Troubleshooting Dot Matrix 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
- 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
- If you are printing totally black pages, suspect
a broken or fouled corona wire. If that is not the case, replace the toner
- 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
- 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
- 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