User manual

98.05.08.09.00
Color LaserWriter 12/600 PS Troubleshooting 2–12
Startup Tests
When you switch on power, all the status panel lights illuminate briefly.
This confirms that power is getting to the status panel and that all LEDs
are operational. The lights then extinguish and the four primary lights
come back on. This marks the start of the Power-On Self-Test (POST).
POST is a set of diagnostic procedures that are written into firmware on
the I/O controller board. POST occurs during normal printer startup.
Power-On
Self-Test
(POST)
POST checks the following four areas of the printer:
Stage 1 I/O controller (CPU & SIMMs)
Stage 2 I/O controller (miscellaneous)
Stage 3 Printer engine
Stage 4 Optional hardware
POST extinguishes the primary lights left to right as each test stage
passes. In a functional printer, the testing process takes about 40
seconds, after which the normal warmup continues. However, if POST
detects a fault during any stage, the status panel enters an error state and
flashes the Paper Out and Paper Jam lights forever. At this point, no
further printer operation is possible until the fault is resolved.
Note
: The QuickTime movie to the left shows the behavior of the
status panel when a POST error is encountered during startup. The
“POST Codes Matrix” follows later in this topic.
Observation of the primary lights prior to an error array can be an effec-
tive I/O controller confidence test. If the Ready and Consumable lights
extinguish during POST, stages 1 and 2 have passed, signifying that the
I/O controller is functional.
When the primary POST error array occurs, some combination of
secondary lights also illuminates. This secondary array isolates the
error designation to the module or piece-part level. To decipher the
meaning of the secondary lights, ask yourself two questions: which
lights are on to the left of the graphic, and how many lights are on to the
right of the graphic? Then refer to the matrix to see what service action
is required.
POST/Detected Error
Movie
!
MC
Bk
Y
Which How Many