Hardware Reference
In-Depth Information
This can indicate a problem with only that unit or its location, but if you see it on more than one
monitor of the same make, it might indicate a manufacturing problem; it could also indicate
problems with the signal coming from the graphics card. Move the monitor to another system
equipped with a different graphics card model, and retry this test to see for certain whether it's
the monitor or the video card.
• Display the Microsoft Windows desktop to check for uniform focus (with CRT displays) and
brightness (with CRT and LCD displays). Are the corner icons as sharp as the rest of the
screen? Are the lines in the title bar curved or wavy? Monitors usually are sharply focused at
the center, but seriously blurred corners indicate a poor design. Bowed lines on a CRT can be
the result of a poor video adapter or incorrect configuration of the monitor's digital picture
controls. Before you decide to replace the monitor, you should adjust the digital picture controls
to improve the display. Next, try attaching the monitor to another display adapter. If the display
quality does not improve, replace the monitor.
Adjust the brightness up and down to see whether the image blooms or swells, which indicates
the monitor is likely to lose focus at high brightness levels. You can also use diagnostics that
come with the graphics card or third-party system diagnostics programs to perform these tests.
• With LCD panels in particular, change to a lower resolution from the panel's native resolution
using the Microsoft Windows Display properties settings. Because LCD panels have only one
native resolution, the display must use scaling to handle other resolutions full-screen. If you are
a web designer, are a gamer, or must capture screens at a particular resolution, this test will
show you whether the LCD panel produces acceptable display quality at resolutions other than
normal. You can also use this test on a CRT, but CRTs, unlike LCD panels, are designed to
handle a variety of resolutions.
• A good CRT monitor is calibrated so that rays of red, green, and blue light hit their targets
(individual phosphor dots) precisely. If they don't, you have bad convergence. This is apparent
when edges of lines appear to illuminate with a specific color. If you have good convergence,
the colors are crisp, clear, and true, provided there isn't a predominant tint in the phosphor.
• If the monitor has built-in diagnostics (a recommended feature), try them as well to test the
display independently of the graphics card and system to which it's attached. A display with
built-in diagnostics shows text or a test pattern onscreen if it is receiving power when the host
system is turned off or if the monitor is not connected to a host system.
Adjusting Monitors
One embarrassingly obvious fix to monitor display problems that is overlooked by many users is
adjusting the monitor controls, such as contrast and brightness. Although most recent monitors use
front-mounted controls with onscreen display (OSD), other adjustments might also be possible.
Older CRT monitors, for example, may have a focus adjustment screw on the rear or side of the unit.
Because the adjusting screw is deep inside the case, the only evidence of its existence is a hole in the
plastic grillwork. To adjust the monitor's focus, you must stick a long-shanked insulated screwdriver
about 2 inches long into the hole and feel around for the screw head. This type of adjustment can save
you an expensive repair bill. Always examine the monitor case, documentation, and manufacturer's
website or other online services for the locations of adjustment controls.
Virtually all recent monitors use digital controls instead of analog controls. This has nothing to do
with the signals the monitor receives from the computer, but only the controls (or lack of them) on the
 
 
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