Top 10 Xerox Phaser 8400 Laser Printer Questions & Answers

Replacing the pring head.
1. Remove the side covers.
2. Remove the ink loader assembly. There are 2 connectors on the ink loader. SO remove it slowly.
3. Remove the spring guides on the print head. One on each side, Held in my one torx screw.
4. Remove the spring bracked assembly on the left side of the printer, it puts pressure on the XY axis motor to position the print head. Just pop it off and position it up and to the left of the bracket.
5. Remove the steel square block on the left bottom side of the frame.
6. Unplug the harness and ribbon cables and then from the back of the printer, remove the print head, be careful not to hit the drum.
Install the print head, the ribbon cables are somewhat difficult to plug back in, Just be patient. and make sure they are conneted firmly. Also when replacing the cables and harness, be sure they are routed corectly so the print head does not get bound on them.
Set the print head into position and install the steel block, then the spring bracket on the XY motor, then the spring brackets in the proper positions. Dont forget to put that spring bracket back on, It is easy to over look.
Make sure all things are plugged in on the print head.
Next reinstall the ink loader, make sure all connectors are connected.
Install the covers and you are done.
Take your time, probably should take about an hour. Just to it carefully and methodically.

This is a print head position issue.

TRY FIRST (Solutions without parts):
1. Check that the wipe mechanism has homed. 2. Check the printhead position and verify that it has initialized properly / manually home the printhead and power cycle the printers power and check for the error to return. If not then the error was most likely due to non-process function (something out of sequence).
Part likely to be the cause:
GEARBOX AND MOTOR,PROCESS DRIVE - PL 4.0, Item 14.

Problem:
The machine displays the Replace Maintenance Kit after the Maintenance Kit has been replaced.
Cause:
There may two causes for this issue.

1. The machine does not recognize that the Maintenance Kit was removed. This would likely be caused by a defective Drum Maintenance Pivot Plate.
2. The machine corrupts the CRUM on the new Maintenance Kit. This may be caused by a defective Drum Maintenance Pivot Plate or IO Board.

1. While the Replace Maintenance Kit message is displayed, remove the Maintenance Kit. If the displayed message does not change to "Maintenance Kit Missing," replace the Drum Maintenance Pivot Plate and install a new Maintenance Kit.
2. While the Replace Maintenance Kit message is displayed, remove the Maintenance Kit. If the displayed message changes to "Maintenance Kit Missing," replace the IO Board and then install a different NEW Maintenance Kit. If the problem persists, replace the Drum Maintenance Pivot Plate and install a different NEW Maintenance Kit.

When you go into the eliminate light stripes there is also a mode called Jet Substitution. You can sometimes bypass the bad jets.
If that does not work then the print head will most likely need to be replaced.
You can replace the printer for less than the cost of a print head normally..

What you are describing is a bad print head. You can try running the eliminate light stripes several times, and jet substitution, but most likely the print head will have to be replaced to remedy your problem.
You can try googling. Phaser printer print heads or phaser printheads.
There seems to be a secondary market appearing for those print heads. I can tell you from Xerox, if you have no maintenance agreement, they cost $750 per print head.
Honestly, having worked on about every type of color printer known to man, the new solid ink phaser printers, produce a dry ink image of 2400 x 2400 dpi with ink particles that align end to end. The resolution of those printers are remarkable and can be purchased for less than the price of one of those new print heads.
Now for reliable, albeit somewhat not as sharp a color image, but still exceptional, you really can not beat an HP.
The ink stick technology really no longer has the color vividness advantage it initially had. The inks that align end to end, have ended that advantage and are sure a lot cheaper to operate per page.

37,0XX.xx Errors - PEST Faults
AC power supplied by power sources such as uninterruptible power supplies
(UPSs) or DC-to-AC inverter systems may not supply correct voltage to
properly power up the printer. Likewise, other devices sharing the same AC
circuit can cause AC voltage sags that cause the printer to fail its AC heater
PEST tests (Print Engine Self Test). The printer may produce any of the
following disconnected heater errors:
■ Printhead jet-stack 37,002.47 or 37,003.48

Error Messages and Codes
■ Reservoir heater, 37,004.40 or 37,005.41
■ Drum heater error 37,006.42
■ Preheater error 37,008.44
■ Ink melters errors 37,009.45 thru 37,013.40
The printer includes several heaters powered by AC. The printer itself can
power up despite insufficient or irregular AC voltage but it may fail its AC
heater tests. This is due the test not measuring sufficient current flowing
through the heater at the moment the test runs.
Devices sharing the printer’s AC circuit shared, such as a laser printer, a
coffee maker, or a space heater, may be placing heavy intermittent demand
on the AC circuit. This sudden inductive demand creates momentary AC
voltage sag that causes the PEST test to fail.
Verify the AC power source prior to troubleshooting these errors. For wiring
diagrams to aid in diagnosing PEST faults, see “Wiring Diagrams” on
page 10-1.
8400/8500/8550/8560 PEST Description
37,001.46: Generic PEST error. Something went wrong during the PEST process.
37,002.47: PEST Error - Printhead Left jetstack disconnect. The left jetstack is
not drawing the expected power from the supply.

1. Open Start menu.
2. Click on "Printers and Faxes"
3. Double-click the icon for your printer.
4. On the menu bar, click "Printer" to open the printer menu. Click on "Use Printer Offline" to remove the check mark. This will bring your printer back online.

If this did not help, check the printer itself & make sure it is not set to be offline.

kindly check externally the fuser is heating or not. i SUSPECT THE FUSER MIGHT BE FAILED.

You can download the driver directly from here:

http://www.support.xerox.com/go/results.asp?Xtype=download&prodID=8400&Xlang=en_US&Xcntry=USA&source=XOG

Just select which version of Windows 7, and the language.

Hope this helps. If so, please rate. Thanks.

Try printing a light stripes test page (Troubleshooting, print quality problems, troubleshooting print quality page).

If you do not appear to have many missing jets but the colours are all just wrong it may be that the ink has gone stale. Run a couple of head cleans and you should see the colours start to improve. If it is getting better, all you can do is keep running head cleans until you have replenished all the ink in the printhead well.
This problem is common in situations where a lot of black and white printing is done, with very little colour.
Alternatively, it could be that your wiper/cleaning blade is not cleaning the head properly and is smearing the different coloured inks across the head, or possibly that your printhead is leaking colours but I think the first solution should solve your problem.
Hope this helps.