Obtaining Serial Back Channel Traces - Xerox Phaser 7400 Service Manual

Obtaining Serial Back Channel Traces

In rare cases the printer may exhibit unusual behavior that is difficult to troubleshoot.
In such cases, if feasible, it can be useful to obtain a back channel trace from the
printer's Serial Debug Port. The back channel trace, lists step-by-step what the printer
is doing up to the point that an error occurs. The trace may offer clues to help
troubleshoot the problem. Alternately, you can email the trace to your RSS for his
interpretation. You will need the following:
Computer with a serial port
Serial Cable, part number 012-1535-00
Level Adaptor, part number 012-1543-00
To obtain a trace:
1. Connect the Serial Cable and Level Adaptor, then connect the Serial Cable to
your PC. Serial port settings are COM1, 19.2 kbaud, 8 bits, no parity, 1 stop bit,
and hardware control.
2. Turn off the printer.
3. Connect the Level Adaptor with adapter's THIS SIDE UP label facing upwards
to the Serial Debug Port located on the printer's Rear Panel.
4. Start up a terminal program such as in Window's HyperTerminal (usually located
in Programs -- > Accessories --> Communications --> HyperTerminal).
Verify the serial port settings are correct, usually COM1:.
5. Set the printer to Service Mode by grounding the appropriate Mode Select Port
pins (3 and 4).
Note
Service Mode inhibits automatic Startup page printing. Also, the Mode
Select Port jumpers must remain in place to display the printer's operating
system console.
6. Turn on the printer.
The trace should appear in the terminal window. Examine the trace to troubleshoot the
problem. Save the trace as a file, if necessary.
Reference A-29