HP Laserjet 5 Service Manual

Distorted Image or BD Failure
·Make certain the printer is not facing the sunlight.
·The paper may not meet HP’s paper specifications. Select different paper.
·Clean the Laser/Scanner Assembly by blowing compressed air in the slot on the
bottom of the assembly.
·Make sure the two Laser/Scanner connectors are firmly seated.
·Replace the Laser/Scanner unit.
·
Replace the DC Controller.
7-20 Troubleshooting 

Troubleshooting Checks
Engine Test
The engine test print is used to verify that the print engine is functioning correctly.
The Formatter PCA is completely bypassed during an engine test, so this test is
useful for isolating printer problems. The engine test prints a full page of vertical
lines down the entire printable area and is also useful for checking and adjusting
registration.
Engine Test Button Location
The engine test print button is located on the DC Controller PCA. It is accessible
through a...

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...

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:
1Open the Printer Door.
2Remove the toner cartridge.
3Mark the cartridge’s drive gear with a felt-tipped marker. Note the position of the
mark.
4Install the toner cartridge and close the Printer Door. The start-up sequence should
rotate the drum enough to move the...

High-Voltage Power Supply Check
The High-Voltage Power Supply PCA provides the necessary voltages for the
electrophotographic processes. A method for verifying the high-voltage system is
given in the table below.
Toner Cartridge High Voltage Connection Points (1 of 2)
·Charging (1)
·Drum Ground (2)
·Developing Roller (3)
Checks Action
Toner Cartridge Connection Points Visually inspect the three connection points on the
underside, right end of the toner cartridge. If they
are dirty or corroded, clean the...

Toner Cartridge High Voltage Connection Points (2 of 2)
·Charging (1)
·Drum Ground (2)
·Developing Roller (3)
Figure 7-6
7
Troubleshooting
Troubleshooting 7-25 

Paper Curl
Paper curl is inherent to the laser printing processes, and occurs when paper is
subjected to heat. Paper curl tends to relax as the paper cools while resting on a flat
surface. The specification for maximum paper curl when the paper is lying flat
before print is 5 mm (0.2 inches).
Although paper curl cannot be totally eliminated, some steps can be taken to lessen
its impact, as suggested in the following table.
Possible Cause Recommended Action
Paper Path Try using the front output slot to...

Troubleshooting Tools
Paper Path Check
If paper is not being picked up or is not moving through the paper path, you may
want to observe all of the paper motion activities. Overriding PS204 (5L) or SW101
(6L) allows you to observe:
·Motor rotation
·Solenoid action
·Kick plate motion
·Paper Pickup Roller motion
·Drive Roller, Transfer Roller, Fuser Roller and Gear, and Delivery Roller Motion.
To override PS204 and SW101
1Remove the Printer Covers (Figures 6-2, 6-3, and 6-4).
2For HP LaserJet 5LPrinter...

Repetitive Image Defect Ruler
Repetitive Image Defect Ruler
Figure 7-8
7-28 Troubleshooting 

Main Wiring Diagram
Figure 7-9Main Wiring Diagram
7
Troubleshooting
Troubleshooting 7-29