Service manual

LUMISCAN ACR-2000 SERVICE MANUAL – SECTION 7.0 DIAGNOSTICS
7.0 DIAGNISTICS
If a system failure occurs, it is necessary to diagnose the cause before effecting the repair.
This section describes the diagnostic tools and techniques used to isolate various types of system
failures.
7.1 Troubleshooting
The cause of some failures may be obvious. In these cases, the Service Engineer may proceed
directly to the repair.
Before beginning an investigation, it is a good practice to record as much information about the
current state of the system as possible. This information may include, but is not limited to,
symptoms, conditions under which symptoms exist, voltages, settings, cleanliness, and visual state.
Normal generic troubleshooting techniques apply. With knowledge of the system, isolate the failure
to a particular subsystem. With knowledge of the subsystem, trace the symptom back to its cause.
In many cases, failures are caused by lack of periodic maintenance and cleaning. If a system is
known to be behind schedule for its maintenance and cleaning at the time of the failure, it is a good
practice to clean and recalibrate the system before extensive troubleshooting. In many cases this
solves the problem or provides clues as to the cause.
7.2 Symptoms and Their Causes
Here are some of the most common symptoms of system failures and some known causes.
7.2.1 Vertical Lines In Images
If the lines are random within an image but repeatable in each successive image, there is likely lint
blocking the beam near the focal point of the Laser. This is the most common cause of vertical lines.
The procedure for removing lint is in Chapter 6.
If cleaning doesn’t remove the lines, moving the beam up or down a couple of millimeters
sometimes helps. This is done with the 45 degree roof mirror
7.2.2 Horizontal Lines and Banding In Images
The most common cause of horizontal lines is excessive ambient light. Verify that the light present
in the room is 2EV maximum.
In many cases, too much ambient light will create dark horizontal bands at the top and the bottom of
images.