Dell UltraScan P990 User Manual page 26

Table 3-6. Troubleshooting Problems (continued)
Symptom
Picture is fuzzy
Picture bounces or
has wavy oscilla-
tions
Picture is flickering
Picture appears to
be ghosting
Wavy or elliptical
(moire) pattern is
visible
1-18 Dell Model UltraScan P990 Color Monitor User's Guide
Check these items
•
Adjust the contrast and brightness (page 1-5).
•
Degauss the monitor using the OPTION OSD (page 1-9).
If you place equipment which generates a magnetic
field, such as a loudspeaker, near the monitor, or you
change the direction of the monitor, the color may not
be uniform.
The degauss function demagnetizes the metal frame of
the CRT to obtain a neutral field for uniform color repro-
duction. If a second degauss cycle is needed, allow a
minimum interval of 20 minutes for the best result.
•
If red or blue shadows appear along the edges of
images, adjust the convergence using the CONVER-
GENCE OSD (page 1-9).
•
If the moire is cancelled, the picture may become fuzzy.
Decrease the moire cancellation effect using the
OPTION OSD (page 1-9).
•
Isolate and eliminate any potential sources of electric or
magnetic fields. Common causes for this symptom are
electric fans, fluorescent lighting and laser printers.
•
If you have another monitor close to this monitor,
increase the distance between them to reduce the
interference.
•
Try plugging the monitor into a different AC outlet, pref-
erably on a different circuit.
•
Try using the monitor with a different computer in a dif-
ferent room.
•
Refer to your computer system's manual and change
your display refresh rate settings so they match the
monitor's capabilities.
•
Eliminate the use of video cable extensions and/or video
switch boxes. Excessive cable length or a weak connec-
tion can produce this symptom.
•
Cancel the moire using the OPTION OSD (page 1-9).
The moire may be modified depending on the con-
nected computer.
•
Due to the relationship between resolution, monitor dot
pitch and the pitch of some image patterns, certain
screen backgrounds sometimes show moire. Change
your desktop pattern.