Mode Select Port - Xerox Phaser 7400 Service Manual

Mode Select Port

The Mode Select Port (J390), accessible from the Rear Panel, is a 6-pin port used to
place the printer in one of two operational modes or to reset the Image Processor
Board. To access these modes, turn off the power and connect a jumper between the
pin or pins indicated in the following table and either pin1 or 6. When power is
restored, the printer boots in the selected mode.The Mode Select Port pins are
arranged in numeric order with Pin 1 nearest the power cord connection. Pins 1 and 6
are tied to a common ground with the Rear Panel.
Caution
To reset the Image Processor Board, momentarily ground pin 5, and then
immediately re-open the connection. Grounding pin 5 for more than a few
seconds could damage the processor.
Mode Select Port Settings
Mode
Printer Reset
Customer
Service
Reset is a hardware reset of the Image Processor Board.
Customer Mode is the normal mode for printing. The Serial Debug Port is
receiving PostScript back channel information.
Service Mode inhibits printing of the Startup page and causes POST to treat all
errors as Hard Faults. See "Power On Self Test (POST)" on page 4-3. Service
Mode also switches the Serial Debug Port from PostScript back channel
information to the printer's operating system console.
A-28
1 2
GND
GND
GND GND
Phaser 7400 Color Printer Service Manual
3 4
GND
GND
5 6
GND
GND
GND