Printronix L1024, Maintenance Manual

Page: 165 / 372

8–33 Chapter 8 – Power Supplies
HVPS ADJUSTMENT PROCEDURE
1. Turn off the printer.
2. Open the printer and remove the OPC Drum Unit and the Developer Unit.
3. Set the user-adjustable developer bias knob to “3”.
NOTE: The user-adjustable developer bias knob is the green knob located on the
top of the HVPS. This knob is also called VR21. Turning the knob varies
the high voltage to the developer unit.
See Figure 8–19.
4. Disable the following:
S
Paper empty switch
S
Cover interlock switch
S
Top-of-form switch
S
OPC drum switch
5. Turn on the printer and wait for the printer to display the error message, “03 ADD TONER
AND CHK WASTE BOTTLE” on the LCD.
6. Take the printer offline by pressing the On Line key. The top line of the LCD should show
“OFFLINE”.
7. Press the Next key until “DIAGNOSTICS” appears on the bottom line of the LCD.
8. Press the Down key. Press Next until “TEST PRINT” appears on the bottom line of the LCD.
9. Press Down. Press Next until “NO. OF PAGES” appears on the bottom line of the LCD.
10. Press Down. Press Next until “CONTINUOUS” appears on the bottom line of the LCD.
11. Press Enter. (If you receive the message “ENTER SWITCH LOCKED”, then unlock it by
pressing Up and Down simultaneously. Then press Enter again.)
The number of pages to print has now been set to “Continuous”. This is indicated by an
asterisk (*) character on the LCD.
12. Press Up. Press Next until “START TEST PRESS ENTER” appears on the LCD.
13. Press Enter. The message “TEST PRINTING” appears on the LCD. At this point, the printer
should be attempting to print.
14. Using a high voltage probe and a DVM, check the voltages at the points listed in the table on
page 8–31.
NOTE: A high voltage probe must be used when measuring each of these
voltages. Even a good DVM used without a high voltage probe will load the
circuit enough to produce erroneous readings.