Text preview for : 03_troubleshoot.pdf part of Xerox Phaser 740 wanted service manual
Back to : 740.part1.rar | Home
Troubleshooting
This topic discusses troubleshooting the printer. Troubleshooting is discussed with two approaches:
s
A step-by-step verification procedure that systematically confirms that particular components of the printer are properly functioning until a problem is found. A symptom/cause scheme that lists particular printer failures and error codes and their possible causes.
s
System power-up sequence
The following lists the chain of events that occur when you turn on the printer. Follow this list as one means of determining if the printer is operating correctly. When the power switch is turned on, these events occur:
s s s s
The engine control board checks its RAM. All the engine fans are turned on to ensure they work properly. The fuser heater (a halogen lamp) is activated to heat up the heated roller. The position of each toner cartridge is checked to ensure they are in their parked positions. The print engine checks to see that the imaging unit and the paper feeder are installed. The engine motors are rotated to ensure that their rotation sensors are detected. A check is made to determine if any paper is jammed in the printer. The print engine checks the level of toner in each toner cartridge. After the fuser reaches its idle temperature the printer is placed on line in its READY state.
s
s
s s s
The print engine is initialized. If the startup page feature has not been disabled and no error occurred with the printer, the printer prints a startup page.
Service Guide
31
Print engine troubleshooting
This topic is a step-by-step procedure for systematically verifying particular aspects of the printer's operation. Following this procedure should lead to the cause of a printer's failure.
Testing the print engine
1. If the printer does not power up, or does not initialize, or the printer
initializes but the motors do not run properly, go to the later topic, "Verifying power supply operation" on page 33.
2. Observe that the Ready message is displayed on the front panel. If it is not,
go to the later topic "Verifying power supply operation" on page 33.
3. Verify that the image processor's health LED is flashing. The health LED is
viewable through the grill behind the manual feed tray (when the tray is lowered).
4. Press and hold the test button for 4 seconds (on the rear of the printer in the
center of the rear cabinet panel). The print engine responds by making a parallel line test print. If the printer prints a test print, then the printer's print engine is working correctly. Proceed with the next topic, "Verifying printer operation by using its self-test print" on page 33. If the printer does not make the test print, then a problem exists with the printer. Proceed with the topic, "Verifying power supply operation" on page 33.
32
Phaser 740 Color Printer
Verifying printer operation by using its self-test print
1. If not already on, turn on the printer. If the printer does not power up, or
does not initialize, or the printer initializes but the motors do not run properly, go to the next topic "Verifying power supply operation."
2. When the Ready message is displayed, press the Menu button to enter the
menu.
3. Press the scroll buttons to navigate to the Test Prints menu item. Select any
test print.
4. Press Print to print a test prints. The printer should print a test page from
the image processor memory. If the printer prints a test pattern, then the print engine and image processor are working correctly and the printer's problem resides with the network or host interface. Refer to the appropriate topics in Chapter 3 "Verifying the Printer and Host Connections."
Verifying power supply operation
Required tools #1 Phillips screwdriver s Volt-ohm-meter (VOM)
s
Verifying the power supply involves four steps:
s s s s
Measuring the input and output voltages. Checking the power supply fuse(s). Checking its safety interlocks. Testing for a shorted motor which would shut down the power supply or damage the engine control board.
Measuring power supply voltages
1. Turn off the printer and unplug it from its power outlet. 2. AC Input: With the VOM set to measure AC voltages, measure for power
being supplied to the printer. It should measure between 87 to 128 VAC (115 VAC nominal) or 174 to 250 VAC (220 VAC nominal).
3. Power supply fan: With the power switch on, is the main fan running? If
not, check the fan's wiring harness (CN9) to the engine control board; it should measure 24 VDC. If the voltage is not correct, replace the engine control board. Otherwise, replace the power supply fan.
Service Guide
33
DC Output: With the VOM set to measure DC voltages, measure voltages at CN301 for +5 VDC and +24 VDC. If the voltage is not correct, replace the power supply. The following illustration shows the test points.
Power supply 9
1
CN 301 Pin 9 - +24 V Pin 8 - GND Pin 7 - GND Pin 6 - GND Pin 5 - +24 V Pin 4 - +24 V Pin 3 - GND Pin 2 - +5 V Pin 1 - +5 V
3102-06
Measuring the DC voltages (test points)
If DC voltages are not being output by the power supply, proceed to the next step, "Inspecting the power supply fuses" on page 35. If the +5 and +24 VDC voltages measure correctly, but the printer does not operate correctly, then proceed to the topic, "Safety interlocks."
34
Phaser 740 Color Printer
Inspecting the power supply fuses
The 115 VAC power supply features a 8 A and a 10 A fuse. The 220 VAC power supply fuse uses a 4 A and a 5 amp fuse.
1. Turn off the printer. 2. Remove the power supply. 3. Remove the power supply cover to access the fuses. 4. Visually, and with a VOM, check to determine that the fuse is in working
order. If the fuse is good, but the printer's power supply does not output DC voltages, proceed to the next topic, "Testing for a shorted motor."
Safety interlocks
The printer features four safety interlock switches:
s s s s
Front door-opened switch. Right side door-opened switch. Left door-opened switch. Optional Lower Tray Assembly door switch.
When any of the switches are opened, the +24 VDC supply to the motors is shut down, as well as the high-voltage power supply.
1. Test the functionality of the interlock using the service tests described in
"Service tests" on page 57.
2. Turn off the printer. 3. With a VOM, set to measure resistance, test each switch when it is opened
and closed.
4. Inspect each switch's wiring harness for pinches, nicks or open connections.
If you find a switch that is defective, replace it. If the switches work correctly and the DC voltages are correct, then the problem may be an open or otherwise faulty motor.
Service Guide
35
If no motors appear to be at fault, replace the engine control board.
Right side door interlock switch Front door interlock switch
Left door switch
Optional lower tray assembly door switch
3102-07
Door safety interlock switches
36
Phaser 740 Color Printer
Testing for a shorted motor
1. Remove the cabinet top and rear access panel. 2. Refer to the topic "Wiring Diagram" on page 113 for a diagram that locates
each connector.
3. Disconnect the motor harnesses. 4. Turn on the printer again to see if it overloads now that the motors are
disconnected from the engine driver board. If the motors and solenoids are functional, but the power supply still does not function, replace it.
Media jams and the paper path
s
Required tools #1 Phillips screwdriver s VOM
Jams fall into the following four categories:
s s s s
Media-based problems Paper-picking errors Printing jams Paper-ejecting errors
Media-based problems
Media problems
1. Test the paper path using the service tests described in "Service tests" on
page 57.
2. Check that the correct type of media is being used. The customer should be
using a quality laser printer paper. The printer may have trouble picking slick-finish paper.
3. Inspect the paper for bent, torn or folded corners. 4. Ensure that the correct media is loaded in the paper tray. 5. Transparency film should only be used from a transparency tray or multipurpose tray.
6. Refer to the media specifications in the table "Functional specifications," on
page 17.
Service Guide
37
Multiple-sheet pick
1. Is the paper in good condition and appropriate for a laser printer? Quality
office laser printer paper works best.
2. Is the printer printing within its environmental specifications? 3. Ensure the corners or the paper are under the tabs in the corners of the tray. 4. Clean the pick rollers. 5. Replace the paper tray.
The media skews passing through the paper path
1. Make sure that the media is properly installed in the tray. 2. Does the pick-up roller pick up evenly? Is it clean? 3. Are the tray's side paper guides snugly adjusted against the stack of media?
The guides, while not adjustable, should be neither too loose nor too tight.
4. Is the paper tray damaged or obstructed? 5. Is there an obstacle blocking the paper path? 6. Is the media excessively curled? 7. Is the customer using an appropriate type of media a type the printer can
handle?
8. Ensure the corners or the paper are under the tabs in the corners of the tray. 9. If the paper only skews when feed from the upper tray, replace the left door.
Paper tray indicates empty when it is not
The procedure for troubleshooting this problem applies to the Lower Tray Assembly as well.
1. Does the paper empty flag properly interrupt the paper empty sensor on the
paper feeder board? Open the left door to observe the flag in action.
2. Test the sensor using the service tests described in "Service tests" on
page 57.
3. Does the paper feeder, when installed, properly connect to the print engine?
Is the paper feeder's wiring harness properly connected to the engine control board (CN20)? (For the Lower Tray Assembly, check connector CN19). Inspect the wiring harness for defects.
4. Replace the paper feeder. 5. Replace the engine control board.
No paper feeder installed
1. Check to see if the paper feeder is properly installed in the printer and
making good electrical contact. Push it in all the way.
38
Phaser 740 Color Printer
2. Ensure that the wiring harness leading from the paper feeder to the engine
control board is properly installed in connector CN20. Check the wiring harness for defects.
3. Replace the engine control board.
No imaging unit installed
1. Ensure that the imaging unit is properly installed and locked in place. 2. Check the main charge grid boss on the rear of the charger to ensure it is not
broken. When the imaging unit is installed, the boss pushes a flag on the charger sensor board. Replace the charger or imaging unit if it is broken.
3. Test the sensor using the service tests described in "Service tests" on
page 57.
4. Check the high-voltage terminal connectors for the imaging unit to ensure
that they are not damaged.
Jams
Paper mis-picks at the paper tray
1. Is the paper in good condition and appropriate for a laser printer? 2. Is the printer printing within its environmental specifications? 3. Is the pick-up roller dirty? If so, clean it and try printing again. You can
also slide off the "treads" from the pick rollers and reverse them to present a fresh pick-up roller edge to the paper.
4. Does the pick roller rotate? Mark the end of the pick roller shaft. Open the
front door and defeat the door open interlock to see the shaft turn.
s
If the roller does not rotate, does the paper feed motor run? Check the motor's wiring harness and connection (CN20) to the engine control board. Check the gear train for broken teeth and proper installation. Replace the paper feed motor. Replace the engine driver board. If the pick roller rotates out of position with each pick, its clutch is worn. Replace the paper feeder.
s s s s
Service Guide
39
5. If the pick roller does rotate, is the pick roller correctly installed (flat side of
the cam-shaped pick rollers face down prior to picking a sheet of paper)?
s
Does the pick solenoid work properly? It must energize for the pick roller to be engaged and rotate. If it doesn't, replace the paper feed circuit board. Replace the paper feeder.
s
Paper jams midway in the paper feeder
1. Ensure that the pick-up rollers are clean. 2. Check the left side door for burrs or foreign obstructions that could block
the movement of a sheet of paper.
3. Clean the intermediate rollers (pinch roller and drive roller). 4. Check the pinch intermediate roller mounted on the inside of the left door
for even spring tension at each end of the roller. The spring tension should measure about 65 grams when the roller end is in the middle of its travel in its slot.
5. Does the pick-up roller clutch work properly? 6. Try printing using a different paper tray. 7. Transparency film. Do not use transparency film in the lower tray of the
Lower Tray Assembly.
Paper jams at the second bias transfer roller
1. Clean the intermediate rollers. 2. Is the transfer roller correctly installed? 3. Is the transfer roller moving up for image transfer when it should? 4. Does the paper jam sensor flag properly interrupt the sensor? Check the
wiring harness of the paper jam sensor leading to CN607 of the paper feeder board.
5. Does the drive intermediate roller rotate? If not, check the gear train driving
the gears for proper installation and for broken teeth.
6. Check the left side door for burrs or foreign obstructions that could block
the movement of a sheet of paper.
7. Check the pinch intermediate roller mounted on the inside of the left door
for even spring tension at each end of the roller. The spring tension should measure about 65 grams when the roller end is in the middle of its travel in its slot.
8. Clean the aligning rollers. 9. Do the aligning rollers rotate during a paper pick? Determine if the aligning
roller clutch operates correctly.
10. Check that the paper feeder wiring is properly installed and that the wiring
harnesses are not damaged.
40
Phaser 740 Color Printer
11. Check the spring pressure at each end of the aligning rollers. Lifting each
end of the roller with a tension gauge should reveal a measurement of about 1 kg (2.2 lbs).
12. Check the left side door for burrs or foreign obstructions that could block
the movement of a sheet of paper. Check for a paper scrap in the paper guide.
13. Try printing using a different paper tray.
Fuser jams
1. Is the paper in good condition and appropriate for a laser printer? 2. Is the printer printing within its environmental specifications? 3. Is this a duplex print with heavy printing (lots of toner coverage) on the
first-printed side? Print the light-printing side first.
4. Is the heat shield plate at the entrance of the fuser loose and obstructing the
paper path?
5. Inspect the fuser's gear train leading to the paper feed motor. Does it rotate
properly? Do any of the gears show broken teeth?
6. Does the fuser exit sensor flag properly actuate its sensor? 7. Inspect the wiring harnesses leading from the cartridge sensor/eject unit to
CN21 of the engine control board.
8. Inspect the fuser roll. If it is empty, replace the fuser roll. 9. Observe if the exit rollers rotate during the print process. If they do not,
reinstall the fuser to ensure its gear train (which also drives the exit roller) properly connects to the paper feed motor.
10. Replace the fuser. 11. Replace the engine control board.
Service Guide
41
Eject jams
1. Is the paper in good condition and appropriate for a laser printer? Is the
paper curling?
2. Is the printer printing within its environmental specifications? 3. Is the jam caused by a heavy, stiff paper being printed in face-down mode?
In such cases, face-up mode or a lighter grade of paper should be used.
4. Is the paper excessively curved after passing through the fuser that the
reverser (eject unit) can't flip the paper? Try flipping the paper over in the tray.
5. Clean all the eject rollers. 6. Inspect the interior of the printer reverser of the toner cartridge selector/
paper eject unit. Ensure that the metal fingers inside the reverser are not bent or interfere with paper movement.
7. Does the paper exit sensor flag properly actuate its sensor? 8. Inspect the wiring harness leading from the cartridge sensor/eject unit to
CN308 of the engine driver board.
9. Replace the cartridge selector/eject unit. 10. Replace the engine control board.
Multi-purpose tray feed jams
1. Is the paper in good condition and appropriate for a laser printer? 2. Is the printer printing within its environmental specifications? 3. Do not overload the multi-purpose tray; otherwise jams will occur. Check
the position of the media thickness selector at the paper feeder (inside the left door).
4. Clean or replace the multi-purpose feed pick roller. 5. Is the picked media properly interrupting the aligning sensor? 6. Is the multi-purpose feed sensor empty flag properly interrupting the multipurpose pick sensor?
7. Check the wiring harness between the multi-purpose sensor circuit board
and the paper feeder board (connector CN607). Ensure that the wiring harness is not damaged.
8. Check the wiring harness leading from the paper feeder to the engine
control board (connector CN20).
9. Replace the paper feeder circuit board. 10. Replace the engine control board.
Jams in the auto-duplex unit
1. Is the auto-duplex unit correctly installed? 42
Phaser 740 Color Printer
2. Clean the rollers inside the auto-duplex unit. 3. Inspect the duplex unit for foreign objects such as a shard of paper. 4. Does the auto-duplex unit's clutch operate correctly? Refer to "Service
tests" on page 57.
5. Inspect the auto-duplex unit's electrical connector for damage. 6. Replace the auto-duplex unit.
Other problems
These problems may be indicated as errors on the front panel.
The printer continuously displays "Initializing"
The most likely cause is that the image processor has not loaded its EEPROM contents (instructions) into RAM successfully. This is usually indicated by the health indicator LED (heart beat) being on or off but not flashing. All print engine operation halts, and will only become ready when the image processor has successfully booted.
1. Re-powering the printer, or perform a NVRAM reset. 2. To verify if the image processor has failed: a.
Power down the printer, and remove the back of the printer to gain access to the ribbon cable connecting the image processor board to the print engine control board; disconnect the ribbon cable at the control board. Power-up the printer. Wait at least 5 minutes while the print engine initializes. If there was a problem with the image processor, it will now not affect the print engine control board. Check if the print engine is OK by pressing the print engine test print button, you should get the parallel line test print. If not, then your problem is most likely associated with the print engine control board, and you will need to replace it. If, however, you get the print engine test print, then your most likely cause is the image processor.
b.
c.
No toner cartridge installed message when it is
1. Ensure that the toner cartridge is correctly installed. 2. Replace the toner cartridge. 3. Replace the toner cartridge drive unit. 4. Replace the engine control board.
Service Guide
43
No fuser installed message when it is
1. Ensure that the fuser is correctly installed. 2. Check the fuser's connection and wiring. 3. Check the wiring harness leading to the fuser power connector. 4. Replace the fuser. 5. Replace the engine control board.
No fuser roll installed message when it is
1. Ensure that the fuser roll is correctly installed. 2. Check the fuser's connection and wiring. 3. Check the wiring harness leading to the fuser power connector. 4. Replace the fuser. 5. Replace the engine control board.
Front door open when it is closed
1. Inspect that the front door's interlock for damage. 2. Inspect the cartridge selector/eject unit interlock mechanism for damage. 3. Inspect the front door cartridge selector/eject unit interlock mechanism.
Ensure that when the interlock is actuated by the cartridge selector/eject unit being closed, the interlock switch, mounted on the toner cartridge drive unit, closes (with an audible click).
4. Replace the interlock switch. 5. Replace the power supply. 6. Replace the engine control board.
44
Phaser 740 Color Printer
Left-side door open message when it is not
The procedure for troubleshooting this problem applies to the Lower Tray Assembly as well.
1. Is the left door open switch, located in the lower-left back corner of the
printer, properly in place?
2. Does closing the left door actuate the left door open switch? 3. Is the left door properly in place? Replace the door if it does not operate
correctly.
4. Is the left door open switch's wiring harnesses properly connected to the
engine control board (CN3 24V interrupt)? In the case of the Lower Tray Assembly, is the printer properly seated onto the Lower Tray Assembly with good electrical connection. Try reseating the printer. Check the lower feeder's wiring harness to the engine control board at connector CN19.
5. Replace the left door open switch. 6. Replace the engine control board.
High temperature error
1. Replace the power supply unit. 2. Check the fans. 3. Replace the engine control board.
Low temperature error
1. Ensure the fuser is properly installed. 2. Check the fuser's connection and wiring. 3. Check to see if the fuser's thermo-fuse is open. With an ohmmeter, measure
the top two pins of the fuser's connector. For 110 VAC fuser you should measure 1.6 ohms. For 220 VAC fuser you should measure 5.4 ohms. If it is opened, replace the fuser.
4. Replace the fuser. 5. Replace the power supply unit. 6. Replace the engine control board.
Service Guide
45
High voltage error
1. Replace the high voltage board. 2. Inspect the high-voltage wiring. 3. Replace the imaging unit and check the printer for proper operation. 4. Sequentially replace each toner cartridge and check the printer for proper
operation.
5. Ensure that excessive conductive grease has not migrated and shorted a
high-voltage contact to ground on the second bias transfer roller.
Thermistor open error
1. Check the connector CN27 on the engine control board. 2. Ensure a 110 volt fuser has not been installed in a 220 volt printer; it will
damage the power supply thermistor and require the power supply be replaced.
3. Replace the fuser. 4. Replace the engine control board.
Front panel cycling between READY and WARMING UP
1. Make sure that the fuser, imaging unit, and toner cartridges are well seated. 2. Invoke a test print from the Front Panel to try to get an error message to be
displayed that may be present but, is masked by the front panel cycling between READY and WARMING UP.
3. Make sure all connectors to the circuit boards are well seated and make sure
that the screws holding the boards's in place are tight.
Erratic printer behavior
1. Check the amount of RAM installed in the printer. While more than
192 Mbytes of RAM can be physically installed on the image processor board, it can electrically support no more than 192 Mbytes. Unreliable printer operation can otherwise result.
Installed RAM not recognized
1. Upon power-up, the image processor checks each DIMM for information
such as data width, clock delay, number of address columns and row, refresh rate and more. If the DIMM does not meets the required specifications it will be ignored; no error message will be reported.
46
Phaser 740 Color Printer
Printing and print quality problems
Required tools s #1 Phillips screwdriver s Volt-ohm-meter (VOM)
s s
Conductive grease Ruler
Note
Refer to the later topic, "Test Prints" on page 103 for many examples of print defects.
Blank print
1. Press, and hold for 4 seconds, the rear panel Test Print button to determine if
the print engine will image at all. It should produce a parallel line print. If the engine produces a good parallel line print, the print engine is good and the image processor board is bad. If you get a blank print then the following items may be defective. The engine test print feature only works if a paper tray is installed in the top tray slot.
2. Replace the laser unit. 3. Replace the imaging unit. 4. Determine if the cartridge selector is pushing the toner cartridges into
contact with the photoconductive drum.
5. Replace the toner cartridge drive unit. 6. Replace the cartridge sector/eject unit. 7. Replace the engine driver board.
All-black print
1. Entire print, including margins is black. Remove and reinstall the main
charge grid.
2. Inspect the main charge grid for a broken corona wire. Replace the main
charge grid.
3. Replace the high-voltage board 4. Margins are white, print is black. Replace the image processor board. 5. Replace the engine control board.
Service Guide
47
Missing primary color
1. Replace the toner cartridge of the missing color. 2. Determine if the cartridge selector is pushing the toner cartridges into
contact with the photoconductive drum.
3. Check the wiring harness leading from the cartridge selector/eject unit to
CN308 of the engine control board.
4. Replace the toner cartridge drive unit. 5. Replace the engine driver board.
Light print
1. Is the paper in good condition and appropriate for a laser printer? 2. Check the media type and tray type for proper match. Does the media in
the multi-purpose feeder match the default setting made using the front panel?
3. Is the printer printing within its environmental specifications? 4. Inspect the high voltage connector for poor contact with the second bias
transfer roller.
5. Inspect the path the laser beam travels for contamination. 6. Inspect the action of the cartridge selector to ensure that it is pushing the
toner cartridges into full contact with the photoconductive drum.
7. Replace the imaging unit. 8. Replace the second bias transfer roller. 9. Replace the engine control board.
48
Phaser 740 Color Printer
Repeated spots or lines on print in-line with each other
1. Measure the spacing between the spots. The distance between the repeating
spots indicates the source of the problem.
s
Thin horizontal lines, depending on problem, the distance between lines may range from 1.5 mm (1/20th inch) between each line to 103 mm (4 in.) between each line. The gear are "chattering" in paper feeder. Apply a single drop of molybdenum grease (brown grease) to each gear and let print action work the grease into the gears. Avoid excess grease. 26.5 mm (1 in.): Toner cartridge at 1200 dpi. Replace the toner cartridge. 35 mm (1.3 in.): Toner cartridge at 600 dpi. Replace the toner cartridge. 76 mm (3 in.): Second bias transfer roller. Replace the transfer roller. 43 mm (1.7 in.): Imaging unit drive gear train. 95 mm (4 in.): Imaging unit belt roller defect. Replace the imaging unit. 102 mm (4.1 in): Paper feeder drive gear broken tooth. Replace the paper feeder drive gear. 121 mm (5 in): Fuser roller defect. Replace the fuser.
s s s s s s
s
Dark vertical line in print
1. Inspect the scorotron charger for toner or other contamination. If
contaminated, its charge wire will appear fuzzy.
2. Replace the toner cartridge if the dark stripe is of one primary color. 3. Inspect the photoconductive belt for damage. Replace the imaging unit if
necessary.
4. Replace the fuser.
White horizontal line or band in all the colors of a print
1. Replace the imaging unit. 2. Replace the second bias transfer roller. Inspect it for loose roller contacts.
Grease the end of the roller shaft with conductive grease.
Service Guide
49
Vertical lines in the print
1. Inspect the path the laser beam travels for foreign matter that could block
the beam from striking the photoconductive belt.
2. Check the main charger wire and grid. White streaks are caused by a dirty
grid. Black streaks are caused by a dirty wire.
3. If the line is colored, one toner cartridge may not be outputting toner
correctly. Replace the missing color's toner cartridge.
4. Inspect the second bias transfer roller for a scratch or contamination.
Replace the roller if necessary.
5. Inspect the cleaning blade. Ensure no foreign matter is stuck to it. 6. Are the fuser rollers scratched? Replace the fuser.
Dirty background
1. Inspect the scorotron charger for toner or other contamination. 2. If excess printing in background is of one primary color, replace that color's
toner cartridge.
3. Replace the high-voltage board.
Mis-transfer, missing portions of toner
1. Inspect the heat roller (top roller) of the fuser for scratches or contamination. 2. Replace the fuser.
Dark, irregular steaks in all colors
1. Waste toner box full; replace the imaging unit. 2. Replace fuser.
50
Phaser 740 Color Printer
Ghosting
Ghosting with some images is unavoidable because of the color structure of the images. If a color is used at one part of the image area and the same color is used again at a later area, it is very possible to get ghosting of the first image into the second image area after one revolution of the toner cartridge developer roller. This occurs because the charge that is created from the first use of the color was not totally extinguished. A small residual charge remains associated with the color, resulting in a second use of the color to be darker in the same areas as the first image. This results in the first image ghosting into the second image when the same color is used.
1. A new toner cartridge exhibits less ghosting. Ghosting increase as toner
cartridges age.
Unfused or partially fused printing
1. Is the paper in good condition and appropriate for a laser printer? 2. Is the printer printing within its environmental specifications? 3. Replace the fuser unit.
Image is skewed on the paper
1. Is the paper in good condition and appropriate for a laser printer? 2. Is the printer printing within its environmental specifications? 3. Swap the tray that the affected print originates from. 4. Ensure that the paper feeder is properly installed. Inspect its paper pick
roller. Look for obstructions in the paper path.
5. Clean the intermediate and aligning rollers. 6. Replace the paper feeder.
Stains on the back of the print
1. Do not touch the surface of a second bias transfer roller. 2. Empty the waste bin of the second bias transfer roller. 3. Clean the paper path of the paper feeder. 4. Inspect the fuser rollers for contamination. Replace the fuser. 5. Replace the paper feeder.
Service Guide
51
No printing on edge of print
1. If one primary color is missing, replace that color's toner cartridge. 2. Check that each toner cartridge moves forward smoothly toward the
imaging unit. Also inspect the two metal pads on the ends of the toner cartridge that the toner cartridge selector cams push against.
3. Inspect the cartridge selector/eject unit to ensure that the cams are in good
condition. Replace the cartridge selector/eject unit.
4. Replace the imaging unit.
Image is not centered on the print when it should be
1. Is the paper in good condition and appropriate for a laser printer. 2. Is the printer printing within its environmental specifications? 3. Ensure the paper feeder is properly installed. 4. Is the top and left margin adjustments correct? Refer to the service tests
discussed in the topic "Printer self-diagnostics" on page 57.
5. Clean the intermediate and aligning rollers. 6. Replace the paper feeder. 7. Replace the engine control board. 8. Replace the laser scanner.
The print is wrinkled
1. Check for an obstruction in the paper path, particularly the paper feeder
and the fuser.
2. Is the paper in good condition and appropriate size, weight, grain and grade
for a laser printer?
3. Is the printer printing within its environmental specifications? 4. If possible, you should feed long-grain paper into the printer. Long-grained
paper's grain is parallel to the paper path (the direction the paper travels while it is fed through the printer).
5. If the print is exiting the printer with "dog-ears" (the corners folded down,
check the paper separators metal tabs in the corners of paper tray. Bend the tabs slightly to correct the problem or replace the tray.
52
Phaser 740 Color Printer
Macintosh printing problems
Image never prints
The printer indicates it is receiving data, but nothing comes out of printer or goes back to Ready mode without printing an image.
1. Make sure that the correct Phaser 740 icon was selected in the Chooser. Try
printing the job again. Try printing a different file or from a difference application.
2. In the Chooser, switch background printing off. Try printing the job again.
With newer LaserWriter printer drivers, select foreground printing in the print dialog box.
3. Download the Echo showpage snippet which produces a blank sheet of paper,
to determine if the printer is receiving and processing files.
4. Make sure you are printing with the correct PPD file. 5. Activate Error Handler using the front panel Printer Defaults menu.
Alternately, download the Error Handler utility and try printing the job again. If an error page is printed after printing the job again, call the Customer Support Hotline at 1-800-835-6100 for further assistance. Please have the error page in hand.
6. If available, try printing to a black-and-white PostScript Level 2 printer
(such as an Apple LaserWriter). If the file does not print on the black-andwhite PostScript printer, this may mean that the problem may be application- or network-related.
7. Ensure that the print engine can print by pressing the rear panel TEST
PRINT switch to print an internal test print. A paper tray must be installed in the top tray slot.
Image prints in black-and-white
1. In the Chooser, ensure a color printer icon is displayed next to the Phaser
740 in the list of available printers. This indicates the printer's PPD has been selected and configured.
2. In the print dialog box, make sure that the Color/Grayscale option has been
selected.
3. Make sure that the Phaser 740 icon was selected in the Chooser. Try printing
the job again.
4. Check the version of your LaserWriter driver to ensure that it is version 6.0.x
or higher. Earlier versions of the driver do not support color PostScript.
5. The application may require special instructions to print, such as those
contained in a.PPD file. Check in the Phaser 740 CD-ROM.
Image is rotated 90 degrees
1. In the application's Page Setup, make sure that the image is selected to print
in portrait or landscape orientation as you expect. Service Guide
53
2. Make sure that the tray width sensor is working correctly.
Printer isn't in the Chooser
1. Ensure that the printer is turned on and the rear panel health light is
flashing at a regular rate.
2. Check the Network or AppleTalk control panel to ensure the proper network
or zone is selected.
3. Check to see if the printer has not been renamed or placed in another zone.
You can print out a configuration page which lists this EtherTalk information as well as other information about the printer.
Windows printing problems
Image never prints
The printer's Receiving data message is displayed as if receiving data, but nothing comes out of printer or the printer goes back to Ready mode without printing an image.
1. Under the printer's set up options, set RETRY = 850.
54
Phaser 740 Color Printer