HP LaserJet 4 Service Manual - Page 419

Service Mode The Service Mode should be used only by authorized service personnel. The following can be executed while in the Service Mode: • Print a Service Mode Self Test. • Verify the Page Count, (the page count also is displayed on the standard self test). • Set the Page Count. • Set the Cold Reset Default (This sets the factory default paper size. Use when replacing non-U.S. Formatters). • Set the Diagnostic Functions ON or OFF (for software developers use only). • Demo Page=On/Off. Removes the Demo Page option from the self test menu. • BIG Data=On/Off. Setting BIG Data to ON increases the size of the printer's status Readback Buffer. Service Mode has messages only in English. However, certain messages (i.e. "PCL CONFIG PAGE") that are used in user-mode and in service-mode, are displayed in the selected display language while in Service Mode. The following procedure is used to initiate the Service Mode. 1 Hold down the [Menu+] and [Value+] keys while powering ON the printer. Hold the keys down until SERVICE MODE is displayed. 2 The interrupted power-on self test is resumed. If the test completes successfully, the message SERVICE MODE is displayed. To exit Service Mode, press the Go key. * Indicates factory default. LaserJet 5/5M/5N Printer B-25