Diagnostic Aids; Power-On Self Test (Post) - Lexmark 4227 - Forms Printer B/W Dot-matrix Service Manual

4227-300

3. Diagnostic aids

The printer contains self tests to help find and solve problems. You
do not need to connect the printer to a computer or terminal to run
these tests.
Types of self tests are as follows:
•

Power-On Self Test (POST)

•
Hex Trace Mode (a computer or terminal is needed)
•
Print Tests
•
Error Log
Power-On Self Test (POST)
The Power-On Self Tests diagnose the basic hardware printer
functions and initialize the default value settings. POST starts
automatically when power to the printer is turned on, or when the
printer receives an INIT signal from the controller.
•
The power supply fan comes on.
•
LED Test—All LEDs turn on briefly.
•
LCD Test—All pels of the display are activated twice, and then
"initialize" is displayed.
•
RAM Test—Checks that the CPU can write/read the RAM.
•
ROM Test—Checks that the ROM data is correct.
•
Timer/Interrupt Controller Test—Checks that this function is
working.
•
Button Scan Test—Scans all operator panel buttons.
•
NVRAM Test—Checks that the NVRAM data is correct.
•
The ribbon motor feeds ribbon.
•
The carrier moves to the left side frame, and then back to the
right.
•
The auto Gap sequence occurs.
If any errors occur during the POST tests, an error indicator shows
which test failed. See "Start" on page 2-1.
Diagnostic aids
3-1