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 A+ Practical Application (220-802) Cram Notes

   

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4.8 Given a scenario, troubleshoot, and repair common laptop issues while adhering to the appropriate procedures

1. Laptops, being mobile, usually participate on more than one network, and often use a static IP address at one location and a dynamically assigned IP address at another. For example, your computer might use dynamic addressing (DHCP) at the office but need to use a static IP address when at home to connect to a broadband ISP.

2. Most laptop computers require a function key or software command to activate/deactivate the laptop video output signal. Usually, the activation/deactivation command acts as a toggle switch: repeat the command to display the image on the internal laptop display, the external display (projector) or both displays simultaneously.
Examples: Acer: Fn+F5, Dell: Fn+F8 will activate/deactivate laptop/external display. 

3. The nickel cadmium battery, known as NiCad , used to be the most common type of laptop battery. NiCad batteries could easily be ruined by being left on the charger after they had reached full charge, or by being recharged before they were completely dead. The latter problem, called the "memory effect," meant that if you recharged your laptop battery before it had run completely down, it would remember the point at which you put it back on the charger, and only discharge that far the next time you used it.

4. The nickel metal hydride (NiMH) laptop battery could hold considerably more power than NiCad, but they still had something of a memory effect, although to a lesser extent

5. Lithium ion (Li-Ion) is the latest technology for laptop batteries. They are considerably lighter and does not exhibit memory effect. The Li-Ion laptop battery lasts considerably longer than its predecessors. If your laptop supports Li-Ion battery, then it is a recommended choice.

4.9 Given a scenario, troubleshoot printers with appropriate tools

1. Some of the frequently encountered problems using laser printers and probable causes are as given below:

I. Speckled pages: The causes for this may be

a. The failure to clean the drum after printing properly, or

b. The drum might have developed scratches.

II. Blank pages: The causes for white pages may be,

a. The toner would have dried out, replace the toner.

b. The transfer corona, that is responsible for transferring the toner to the drum might have failed. c. The High Voltage Power Supply (HVPS) failure will also result in white pages.

III. Ghosted Images: Ghosting occurs when previously printed pages are printed again, though much lighter than the present image. The most likely cause is that the erasure lamp might not be working properly, thus leaving some charges representing the earlier image left on the photosensitive drum before new image is written. Also check the cleaning blade, which is responsible for scaping the residual toner.

IV. Smudged images: If the fusing fails, the toner will not bond with the paper. Check the halogen lamp responsible for heating.

2. The following are the 6 steps in the ElectroPhotographic (EP) print process of Laser Printer:

a. Cleaning: Cleaning the photosensitive drum includes residual toner left on the drum and removing the electrical charges left out on the drum. The physical cleaning is done with a rubber blade and the electrical charge cleaning is done with erasure lamps.

b. Charging: The next step in printing, is to charge the photo sensitive drum with high negative charge, this is done with the help of a corona wire.

c. Writing: A laser (type 3) sweeps the entire length of the drum, creating the static image of the matter to be printed. The places where the laser travel, the highly charges are neutralized. Other places of the drum, it remains highly negatively charged.

d. Developing: Now drum gets in close proximity to the toner. Because the toner is negatively charged, it gets attracted to the areas where the drum is neutral. It will not be attracted to the places where the drum is highly negatively charged. Thus the image of the page to be printed formed on the photosensitive drum.

e. Transferring: Now, the toner on the drum gets attracted toward the paper, by using highly positive charges developed on the surface of the paper. The "transfer corona" is used to generate highly positive charge on the paper surface and to attract the toner from the drum. Thus the image of the page to be printed formed on the paper. But still, the toner is loose and can get easily smeared.

f. Fusing: In order to permanently bond the toner particles to the paper, the paper is passed through rollers. One of the rollers, the non stick roller is heated by a high intensity lamp, generating the heat necessary to bond the toner to the surface of the paper.

3. When a printer is installed on a network, default printer permissions are assigned that allow all users to print. Because the printer is available to all users on the network, you might want to limit access for some users by assigning specific printer permissions. For example, you could give all non-executive users in a department the Print permission and give all managers the Print and Manage Documents permissions. You can also deny print permission to all others. In this way, all non-executive users and managers can print documents, but managers can also change the print status of any document sent to the printer.

4. Normally, the printer supplier provides a driver that goes with the XP OS. It is always preferable to use the driver supplied by the device manufacturer along with the printer.

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