Rosewill Computer Case 422 Informacje Techniczne Pobierz pdf (Strona 61)

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Chapter 4 • Disassembly and Power

the device motors found in drives, the CPU, internal cooling fans, and the graphics card. Drives

are now beingmade that use +5V motors. Chips use +5 volts and +3.3 volts. The +3.3 volts are

also used for memory, AGP/PCI/PCIe adapters, and some laptop fans. The negative voltages are

seldom used.

A technician must occasionally check voltages in a system. There are four basic checks for

power supply situations: (1) wall outlet AC voltage, (2) DC voltages going to the motherboard,

(3) DC voltages going to a device, and (4) ground or lack of voltage with an outlet tester. A

power supply tester can be used to check DC power levels on the different power supply con-

nectors.

Mobile Device Travel and Storage

When traveling with a laptop, remove all cards that insert into slots and store them in con-

tainers so that their contacts do not become dirty and cause intermittent problems. Remove

all media discs such as CDs, DVDs, or BDs. Check that drive doors and devices are securely

latched. Ensure that the mobile device is powered off or in hibernate mode (not in sleep/sus-

pend or standby power mode, which is covered later in this chapter).

Carry the device in a padded case. If you have to place the device on an airport security

conveyor belt, ensure that the device is not placed upside down, which could cause damage to

the display. Never place objects on top of a mobile device or pick up a laptop by the edges of

the display when the laptop is opened. When shipping a mobile device, place it in a properly

padded box. The original shipping box is a safe container.

The United States has regulations about lithium batteries on airplanes. If battery contacts

come in contact with metal or other batteries, the battery could short-circuit and cause a fire.

For this reason, any lithium batteries are to be kept in original packaging. If original packag-

ing is not available, place electrical tape over the battery terminals or place each battery in an

individual bag. Spare lithium batteries are not allowed in checked baggage but can be taken in

carry-on bags.

Like other electronic devices, laptops have heating issues. The following can help with lap-

top overheating:

• Locate air vents and keep them unblocked and clean. Do not place a laptop on your lap

to work.

• In the BIOS settings, check the temperature settings for when fans turn on.

• Check the laptop manufacturer website or documentation for any fan/temperature

monitoring gauges.

• Place a laptop on something that elevates it from the desk, such as drink coasters. In

addition, pads, trays, and mats can be purchased with fans that are AC powered or USB

powered.

Mobile Device Power

A portable computer (laptop/netbook/ultrabook/tablet) uses either an AC connection or a bat-

tery as its power source. On most models, when the mobile device connects to AC power,

the battery normally recharges. Laptop batteries are usually modules with one or two

release latches that are used to remove the module.

Smartphone batteries either have a release latch or

you slide part of the phone away and reveal the battery.

Figure 4.27 shows a netbook computer with its battery

module removed. Battery technologies have improved

in the past few years, probably due to the development

of more devices that need battery power, such as tab-

lets, digital cameras, and portable CD, DVD, and BD

players.

Check input voltage selector

Some power supplies and laptops have input

voltage selectors; others have the ability to accept

input from 100 to 240 volts for use in various

countries (dual voltage). Ensure that the power

supply accepts or is set to the proper input voltage.

Tech

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