Sony GDM-W900 Operating Instructions Manual page 38

Troubleshooting
Symptom
Screen image is not centered
or sized properly
Edges of the image are
curved
White lines show red or blue
shades at edges
Picture is fuzzy
Picture bounces or has wavy
oscillations
Picture is not stable
Picture appears to be
ghosting
Two fine horizontal lines
(wires) are visible
Wavy or elliptical (moire)
pattern is visible
Hum is heard right after the
power is turned on
Because of vibration and
shock during transportation,
the Aperture Grille may
occasionally slip out of place
and black stripes may
appear
20
Check these items
• Adjust the centering or size (pages 10, 14).
• Some video modes do not fill the screen to the edge of the monitor. There is no single
answer to solve the problem. This problem tends to occur on higher refresh timings.
• Adjust the geometry items such as pincushion and keystone distortion (page 11, 14).
• Adjust the convergence (pages 11, 14).
• Adjust the contrast and brightness (page 9).
• Degauss the monitor (page 16).
If you place equipment which generates a magnetic field such as a loudspeaker, or you
change the direction of the monitor, color may lose uniformity.
This function is to demagnetize the metal frame of the CRT to obtain a neutral field for
uniform color reproduction. If a second degauss cycle is needed, allow a minimum
interval of 20 minutes for the best result.
• If red or blue shades are found at the edge of images, adjust the convergence (pages 11,
14).
• If the moire is cancelled, the picture may become fuzzy. Adjust so that the picture is as
clear as possible (page 11, 15).
• Isolate and eliminate any potential sources of electric or magnetic fields. Common causes
for this symptom are electric fans, fluorescent lighting, laser printers, and so on.
• 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, preferably on a different circuit.
• Try the monitor on a completely different computer in a different room.
• Set the refresh rate to non-interlace of 75 Hz or more on the computer referring to the
computer's manual.
• Eliminate the use of video cable extension cable and/or video switch boxes if this
symptom occurs. Excessive cable length or weak connection can produce this symptom.
• These wires stabilize the vertically striped Aperture Grille (page 17). This Aperture Grille
allows more light to pass through to the screen giving the Trinitron CRT more color and
brightness.
• Cancel the moire (page 11, 15).
The moire may be modified depending on the connected computer.
• Due to the relationship between resolution, monitor dot pitch and the pitch of some
image patterns, certain screen backgrounds, especially gray, sometimes show moire.
Change your desktop pattern.
• When the power is turned on, the auto-degauss cycle is activated. While the Auto-
degauss cycle is activated, a hum may be heard. This is not a malfunction.
• Lightly pat the sides of the monitor.