Dark streaks Our Phaser 8550 has dark streaks when printing in yellow. O the Light stripes test it shows grey through most of the yellow and some of the pink. I ran the spudge test.

Most likely the cyan ink is burnt. If the ink sticks are left unused (printing more black than color, this will happen.

Print the test pages for PQ troubleshooting from the control panel and examine each print. Cyan will probably have very dark streaks down the page, magenta should look normal, and yellow also will have dark stripes. You need to replace this burnt ink, and the only way is to print. From within paint (or similar accessory in other OS) Create a full page of cyan, and print about 100 - 200 pages, or until the cyan starts to clear up. Yes it is a waste, but much cheaper than a print head, Do this for yellow as well.

Try printing a light stripes test page (Troubleshooting, print quality problems, troubleshooting print quality page).
If you have loads of missing jets, run a couple of head cleans, if you see improvement, it is worth running some more, if not, try switching off overnight and rebooting next day. If it still won't clear, you may have a faulty printhead.
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.
Hope this helps.

If you are using third party ink sticks contact the manufacture and they will, if you use enough of thier product, send you a new print head and send out a tech to change it. Media Science is the most likely source of third party ink.
You can also switch to Xerox ink sticks and the colors will be correct after several purges to get rid of the old ink.

Harry

The best way to tell if your problem is clogged jets, or bad maintenance kit, or something blocking jets. Is to look at light stripes test, and see if missing jets are all in a straight row or all over the place. If the missing jets number less that 10 you can use jet substitution to avoid the streaks. If you are using Media Sciences or some other after market ink, check that most of your problems are not in the cyan area. Media Sciences produced a bad batch of cyan which clogged the jets pretty bad. The good news is that if their ink caused the problem they will pay for some one to come out and replace your printhead. If you LST (Light stripes test) has a smear the entire vertical lenght of the page. You have either a bad maintenance kit, or a piece of paper, lable etc..rubbing against the drum while printing

Yep!
Here you go...
1995 Mercury Villager Car Stereo Radio Wiring Diagram
Radio Constant 12V+ Wire: Green/Purple
Radio Ignition Switched 12V+ Wire: Yellow/Black
Radio Ground Wire: Black/Light Green
Radio Illumination Wire: Green
Radio Dimmer Wire: N/A
Radio Antenna Trigger Wire: N/A
Radio Amplifier Trigger Wire: N/A
Front Speakers Size: 5′ x 7′
Front Speakers Location: Doors
Left Front Speaker Wire (+): Orange/Light Green
Left Front Speaker Wire (-): Light Blue/White
Right Front Speaker Wire (+): White/Light Green
Right Front Speaker Wire (-): Dark Green/Orange
Rear Speakers Size: 5′ x 7′
Rear Speakers Location: Side Panels
Left Rear Speaker Wire (+): Light Brown/White
Left Rear Speaker Wire (-): Light Brown/Yellow
Right Rear Speaker Wire (+): Light Brown/Green
Right Rear Speaker Wire (-): Brown/Pink

That's what they show for factory
K

Resolving white, light lines or streaks (eliminate light stripes)

From the printer, print the Troubleshooting Print Quality Pages.
With Troubleshooting highlighted, press the OK button.
Scroll to Print Quality Problems by pressing the Up or Down Arrow button. Press OK.

Scroll to Troubleshooting Print Quality Page. Press OK.
Evaluate the Light Stripes Test page for missing printhead jets (missing cyan, magenta, yellow or black color bars).

Clean the maintenance unit's wiper blade and empty the waste tray. A dirty maintenance drawer wiper blade can cause white lines and weak or missing printhead jets. Using a clean lint-free cloth or a paper coffee filter, gently clean the blade with a wiping motion across the entire length of the wiper blade.

Appropriate cleaning procedures, as listed in the following tables, should be
performed when specific print-quality or paper transport problems occur.
All cleaning procedures are detailed in the printer’s Phaser 8400 Reference Guide or
the Phaser 8500/8550 User’s Guide.
Light Stripes or Missing Colors
Problem type Solution
Missing or light-colored
stripes on prints.
Select the automated procedure Eliminate Light Stripes from
the Control Panel.
Ink Smears, Oil Spots, or Random Ink Streaks
Problem type Solution
Ink smears on the front,
back, or edges of a page.
Select the automated procedure Remove Print Smears from
the Control Panel.
Check the maintenance kit for ink and paper-dust build-up on
the wiper blade.
Oil (drum fluid) on top edge
of print.
Select the automated procedure Remove Print Smears from
the Control Panel.

Hope this helps
pdouglasss

Dark streaks are an indication of "burned" or overheated ink. This will occur when the printer sets for a long period of time and nothing is printed. The problem will usually disappear after 50 pages or so, unless the printhead is damaged.

If the print remains dark, the printhead will need replaced.
(Very expensive)

(Dark print can also be caused by using Non-Xerox ink)

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..

Select the Jet Substitution Mode.

1. On the Control Panel, select Troubleshooting, and then press the OK button.
   
2. Select Print Quality Problems, and then press the OK button.
   
3. Select Eliminate Light Stripes, and then press the OK button.
   
4. Select Jet Substitution Mode, and then press the OK button.
   
5. Follow the Control Panel prompts to select the color and malfunctioning jet number indicated on the Light Stripes Test page.