Hardware Reference
In-Depth Information
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 re-
centmonitorsusefront-mountedcontrolswithonscreendisplay(OSD),otheradjustments
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
examinethemonitorcase,documentation,andmanufacturer'swebsiteorotheronlineser-
vices for the locations of adjustment controls.
Virtually all recent monitors use digital controls instead of analog controls. This has noth-
ing to do with the signals the monitor receives from the computer, but only the controls
(or lack of them) on the front panel that enable you to adjust the display. Monitors with
digital controls have a built-in menu system that enables you to set parameters such as
brightness (which adjusts the black level of the display), contrast (which adjusts the lu-
minanceofthedisplay),screensize,verticalandhorizontalshifts,color,phase,andfocus.
A button brings up the menu onscreen, and you use controls to make menu selections and
vary the settings. When you complete your adjustments, the monitor saves the settings in
nonvolatile RAM (NVRAM) located inside the monitor. This type of memory provides
permanent storage for the settings with no battery or other power source. You can unplug
the monitor without losing your settings, and you can alter them at any time in the future.
Digital controls provide a much higher level of control over the monitor and are highly
recommended.
Digital controls make adjusting CRT monitors suffering from any of the geometry errors
shownin
Figure12.26
easy.Beforemakingtheseadjustments,besuretheverticalandho-
rizontal size and position are correct.
Figure 12.26
Typical geometry errors in CRT monitors; these can be corrected on most models that have
digital picture controls.
