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HP LaserJet 6p/mp Service Manual - Page 136

Half self-test functional check, Drum rotation functional check, High Voltage Power Supply Check.

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Note Half self-test functional check The electrophotographic process can be subdivided into the following stages: l Cleaning (removing excess toner from drum surface) l Conditioning (placing a uniform electrical charge on drum) l Writing (laser strikes surface of drum to create latent image) l Development (formation of the toner image on drum) l Transfer (charge to transfer the image to paper) l Fusing (heat and pressure to produce a permanent image) The purpose of the Half Self-Test Check is to determine which process is malfunctioning. Perform the test as follows: 1 Initiate a self-test. 2 Open the Printer Door after the paper advances half-way through the printer (about eight seconds after the Motor begins rotation). The leading edge of the paper should have advanced past the toner cartridge. 3 Remove the toner cartridge. 4 Open the toner cartridge's drum shield to view the drum's surface. If a dark and distinct toner image is present on the drum's surface, assume that the first four functions of the electrophotographic process are functioning (cleaning, conditioning, writing and developing - see Chapter 5.) Troubleshoot the failure as a transfer or fusing problem. If NO image is present on the photosensitive drum, perform the following functional checks: 1 Make sure you have removed the entire length of the sealing tape from the toner cartridge before you installed the cartridge. 2 Drum Rotation Functional Check. 3 High Voltage Power Supply Check. Drum rotation functional check The photosensitive drum, located in the toner cartridge, must rotate for the print process to work. The photosensitive drum receives its drive from the Main Drive assembly. To verify whether the drum is rotating: 1 Open the Printer Door. 2 Remove the toner cartridge. 3 Mark the cartridge's drive gear with a felt-tipped marker. Note the position of the mark. 4 Install the toner cartridge and close the Printer Door. The start-up sequence should rotate the drum enough to move the mark. 5 Open the printer and inspect the gear that was marked in step 3. Verify that the mark moved. If the mark did not move, inspect the Main Drive assembly to ensure that it is meshing with the toner cartridge gears. If the drive gears appear functional, and the drum does not move, replace the toner cartridge. This test is especially important if refilled toner cartridges have been used. 134 Troubleshooting EN

Section	Page
Contents	7
Figures	11
Tables	13
Product information	15
Chapter contents	15
Printer features	16
Identification	17
HP LaserJet 6L Gold	17
Model and serial	17
Specifications	20
Product overview	21
Service approach	24
Parts Exchange Program	24
Ordering parts	24
Ordering related documentation	24
Contacting HP to place an order	24
Technical assistance	25
HPCustomer Care	25
HP worldwide sales and service offices	27
Warranty	30
Hardware service during the warranty period	30
Hardware service after the warranty period	30
HP LaserJet Toner Cartridge warranty	31
Voltage conversions	31
Site requirements	33
Chapter contents	33
Site requirements	34
Operating environment	34
Printer space requirements	35
The HP C3906A/F Toner Cartridge	36
Storage conditions	36
Storing opened toner cartridges	36
Toner cartridge handling suggestions	37
Operating overview	39
Chapter contents	39
Using the Control Panel	40
Control Panel layout	40
Indicator lights	40
The Control Panel Button	42
Printing a self-test page	43
Continuous self test	46
Printing an engine test	46
Resetting the printer	47
To reset the printer	47
Printer maintenance	49
Chapter contents	49
Life expectancy of consumables	50
Toner cartridge life	51
Saving toner with EconoMode	51
Refilled toner cartridges	52
Recycling toner cartridges	52
Cleaning the printer	53
Cleaning printer components	53
Cleaning spilled toner	54
Functional overview	55
Chapter contents	55
Basic printer functions	56
DC Controller/power system	57
Print engine control system	58
Power system (on DC Controller PCA)	58
Formatter system	60
CPU	60
Read only memory (ROM)	60
Random access memory (RAM)	60
Parallel interface	60
Control Panel	60
Resolution Enhancement technology (REt)	61
EconoMode	61
Memory Enhancement technology (MEt)	61
Enhanced I/O	61
Page Protect	62
PJL overview	62
Image formation system	63
Toner cartridge	63
Step 1: Drum cleaning	64
Step 2: Drum conditioning	64
Step 3: Image writing	64
Step 4: Image developing	64
Step 5: Image transferring	64
Step 6: Image fusing	64
Paper feed system	65
Paper jam detection	67
Basic sequence of operation	68
Removal and replacement	71
Chapter contents	71
Removal and replacement strategy	72
Required tools	73
Installing memory cards (DRAM)	74
Covers and doors	75
Back Cover	75
EP Door Assembly	77
Memory Door	78
Main Cover and Paper Input Assembly	79
Internal assemblies	80
Control Panel	80
Exit Roller Assembly	81
Delivery Assembly	82
Fuser Pressure Plate	84
Heating Element	86
Pressure Roller	89
Face-Up/Face-Down Lever	90
Fuser Exit Roller Assembly	91
Paper Exit Sensor Flag	92
Top assemblies	93
Laser/Scanner Assembly	93
Solenoid	94
Pickup Roller Assembly	96
Paper Feed Frame	99
Transfer Roller Guide and Transfer Roller	103
Kick Plate	104
Separation Pad	106
Subpads	107
Feed Assembly	108
Bottom assemblies	111
Memory Door Guide	111
Motor	112
DC Controller	113
Formatter PCA	116
Troubleshooting	117
Chapter contents	117
General troubleshooting flowchart	118
Paper path and components	120
DC Controller diagram	121
Printer error troubleshooting	122
Priority of errors	122
Printer status messages	123
Service and error messages	125
Image formation troubleshooting	128
Check the toner cartridge	128
Image defect examples	129
Troubleshooting checks	135
Engine test	135
Half self-test functional check	136
Drum rotation functional check	136
High-voltage power supply check	137
Paper curl	139
Troubleshooting tools	140
Paper path check	140
Repetitive image defect ruler	141
Main wiring diagram	142
Parts and diagrams	145
Chapter contents	145
How to use the part lists and diagrams	146
Ordering parts	146
Ordering consumables	146
Accessories and supplies	147
Common hardware	148
Parts diagrams	149
Parts index	169
Alphabetical parts list	169
Numerical parts list	174
Regulatory information	179
Laser Safety (U.S.)	179
Laser Statement (Finland)	180
Toner safety	181
Ozone emission	181
FCC Statement (Class B)	182
VCCI Statement (Japan)	182

Match case Limit results 1 per page

134

Troubleshooting

Half self-test functional check

The electrophotographic process can be subdivided into the following stages:

Cleaning (removing excess toner from drum surface)

Conditioning (placing a uniform electrical charge on drum)

Writing (laser strikes surface of drum to create latent image)

Development (formation of the toner image on drum)

Transfer (charge to transfer the image to paper)

Fusing (heat and pressure to produce a permanent image)

The purpose of the Half Self-Test Check is to determine which process is malfunctioning. Perform the

test as follows:

Initiate a self-test.

Open the Printer Door after the paper advances half-way through the printer (about eight

seconds after the Motor begins rotation). The leading edge of the paper should have advanced

past the toner cartridge.

Remove the toner cartridge.

Open the toner cartridge’s drum shield to view the drum’s surface.

If a d

ark and distinct toner image is present

on the drum’s surface, assume that the first four

functions of the electrophotographic process are functioning (cleaning, conditioning, writing and

developing - see Chapter 5.) Troubleshoot the failure as a transfer or fusing problem.

NO image is present

on the photosensitive drum, perform the following functional checks:

Make sure you have removed the entire length of the sealing tape from the toner cartridge before

you installed the cartridge.

Drum Rotation Functional Check.

High Voltage Power Supply Check.

Drum rotation functional check

The photosensitive drum, located in the toner cartridge, must rotate for the print process to work. The

photosensitive drum receives its drive from the Main Drive assembly. To verify whether the drum is

rotating:

Open the Printer Door.

Remove the toner cartridge.

Mark the cartridge’s drive gear with a felt-tipped marker. Note the position of the mark.

Install the toner cartridge and close the Printer Door. The start-up sequence should rotate the

drum enough to move the mark.

Open the printer and inspect the gear that was marked in step 3. Verify that the mark moved.

If the mark did not move, inspect the Main Drive assembly to ensure that it is meshing with the toner

cartridge gears. If the drive gears appear functional, and the drum does not move, replace the toner

cartridge.

Note

This test is especially important if refilled toner cartridges have been used.