Datasheet

56
Chapter 1
Hardware
Upgrading Display Devices
Before connecting or disconnecting a monitor, ensure that the power to both the PC and
the monitor is off. Then, connect a VGA (DB-15) cable from the monitor to the PCs video
card, and connect the monitor’s power cord to an AC outlet.
Other than the power supply, one of the most dangerous components to try to repair is
the monitor, or CRT monitor. I recommend that you not try to repair monitors. To avoid
the extremely hazardous environment contained inside the monitorit can retain a high-
voltage charge for hours after it’s been turned offtake it to a certified monitor technician
or television repair shop. The repair shop or certied technician will know and understand
the proper procedures to discharge the monitor, which involves attaching a resistor to
the flyback transformers charging capacitor to release the high-voltage electrical charge
that builds up during use. They will also be able to determine whether the monitor can be
repaired or needs to be replaced. Remember, the monitor works in its own extremely pro-
tective environment (the monitor case) and may not respond well to your desire to try to
open it. The CRT is vacuum-sealed. Be extremely careful when handling it—if you break
the glass, the CRT will implode, which can send glass in any direction.
Even though I recommend not repairing monitors, the A+ exam does test your knowledge
of the safety practices to use when you need to do so. If you have to open a monitor, you must
first discharge the high-voltage charge on it using a high-voltage probe. This probe has a very
large needle, a gauge that indicates volts, and a wire with an alligator clip. Attach the alliga-
tor clip to a ground (usually the round pin on the power cord). Slip the probe needle under the
high-voltage cup on the monitor. You’ll see the gauge spike to around 15,000 volts and slowly
reduce to zero. When it reaches zero, you may remove the high-voltage probe and service the
high-voltage components of the monitor.
If you have a monitor that shows bad distortion, and changing the settings
or Degaussing has no effect, then look for magnetic interference caused by
nearby florescent lights or large power sources.
Using Multimonitor
Multimonitor, also known as multidisplay, is simply using more than one display device for
a single PC. Most PCs allow you to use multiple monitors as long as there is a display card
installed for each. While this can be useful for running a window for each monitor, one of
the most common uses is the Presenter View in Microsoft PowerPoint. When chosen, this
allows a different view of the slideshow to be shown on the main monitor (typically a pro-
jector) than what is shown on the secondary monitor (such as presenter notes, the next slide
that is set to appear, etc.).
Exam Essentials
Know how to deal with display problems. Know that before you begin to work on a dis-
play system, you must take safety precautions because of the power that is stored within.
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