CompTIA 2.4 PC Maintenance (Test-Out)

Configuring a UPS

- let UPS charge for 12-24 hours before plugging anything into it - plug in the system you want protected, be mindful that not all outlets on the UPS are protected by UPS power. - for added protection you can add a USB serial (management) cable that goes from the UPS to the computer, also install drivers to help manage this process.

When Cleaning Removable Devices Use:

- A proprietary cleaning kit, to manually clean the interior of a floppy disc drive. - A cleaning utility program, to automatically clean the interior of a floppy disc drive. - A DDS-approved cleaning tape, to automatically clean the heads of a tape drive. - Compressed air to blow dust and debris off of CD-ROM and DVD disc surfaces, out of drive bays, and off of drive heads. - Soft lint-free cloths, dry, to wipe smudges off of CD-ROM and DVD disc media surfaces.

Cleaning Other PC Components Cont'd:

- For keyboards, use a vacuum or compressed air. For keys that stick use a lint-free cloth and/or cleaning swabs, lightly dampened, to gently wipe each key. - To clean a printer, use a damp or dry cloth. ##On inkjet printers, use the printer's cleaning function to clean the print heads. - For laser printers, use an anti-static vacuum to remove excess toner. A regular vacuum will build up an electrostatic charge from the toner

Maintaining Tips Continued:

- Keep cables organized. Route cables to prevent them from being kinked or stepped on. For best results, use cable ties to bind and organize cables. - Verify that your system's cooling fans are blowing air through the system case in the correct directions. A fan blowing in the wrong direction can negate the airflow through the case and cause the system to overheat.

Heating, ventilation, and air conditioning (HVAC)

- Keep temperature between 70 and 74 degrees to prevent components from overheating. - Keep humidity between 40 and 70 percent to prevent electrostatic discharge (ESD). - Make sure server rooms have separate ducting or systems from the rest of the building for better control. - Use positive pressure systems. Positive pressure systems protect the air quality in the facility by causing air to be forced out through doors, windows, and other openings. Negative pressure systems draw air in, potentially bringing in airborne particles such as dust or smoke. Positive pressure systems are more energy effective. - For areas with heavy smoke or dust, add filters to air intake systems to filter out airborne particulates.

Cleaning Other PC Components:

- Use a small amount of denatured alcohol on a cotton swab to clean electrical connectors (such as those on expansion cards). - When cleaning a CRT monitor screen, spray some glass cleaner on a clean cloth (not on the monitor). For LCD screens, use a lint-free dry cloth or a small amount of isopropyl alcohol (do not use window cleaner or ammonium-based cleaners or paper towels). You can also use special monitor-cleaning solutions or pre-packaged wipes with monitor-safe solution. - For a mouse with a roller ball, clean the ball and the roller contacts on a regular basis.

Additional Tips for Maintaining Your Computer:

- When receiving a new computer or component that has been shipped, let it sit for at least 6 hours (24 hours if it arrives in outside freezing conditions) before applying power. The rapid change in temperature can cause damage to components or can result in condensation within the computer. - Perform regular backups. Backups protect your data if a hard disk fails. - You can use covers and cases to protect some equipment (such as printers) from dust and liquid spills. Be sure to remove covers before use and replace after use.

Types of UPS:

- online UPS; best protection and most expensive; because of constant charge and drain the batteries go fast and have to be replaced. - offline UPS; difference is there is a bridge, the UPS uses the 110v current coming in to charge the battery, however it also bridges the current over to the outlet for the system. Instead of running on battery all the time like for an online UPS, it runs on 110v from the wall all the time. Batteries last a lot longer. This is the type of UPS I have in the office.

UPS

A UPS is designed to provide enough power to shut a system down safely during an extended power outage. Most are not intended as long-term power solutions. The UPS connects to the power source (usually a wall socket), the computer plugs into the UPS, and the UPS is connected through a serial or USB port to the computer. Software on the computer uses this connection to monitor battery life and to detect when the regular power is lost. You can configure the software to shut the system down automatically when the battery charge reaches a certain level.

Cleaning your computer:

Common computer cleaning supplies include: Lint free cloth Compressed air or air compressor Small anti-static vacuum Denatured or isopropyl alcohol Regular, periodic cleaning gives you the chance to inspect all components. Look for worn or failed components. On electrical components, dark areas might indicate a burned out component. Prior to cleaning computer components, power down and unplug components and let them sit for at least 30 minutes to cool.

Important Note:

During certain conditions, such as an electrical storm or when the power supply is constantly going up or down, you might need to unplug the computer to protect it. Simply turning it off might still damage the components because some power remains supplied to the system. In the case of an electrical storm, keeping the system plugged in leaves it susceptible to power spikes.

Electromagnetic Interference (EMI)

Electromagnetic Interference (EMI) is interference that affects wired networking signals. EMI is caused by motors, heavy machinery, and fluorescent lights. Use shielded twisted pair cable to protect signals sent on Ethernet twisted pair cabling. If necessary, use fiber optic cables to eliminate the effects of interference.

Magnetic fields

Magnetic fields located close to a computer can cause undesired effects or even data loss. Floppy drives, hard drives, and tape storage devices use magnetic charges on a disk or tape for storing data. While hard disks are shielded and protected from all but the strongest magnets, be careful with floppy disks and tapes. Getting a magnet too close to these components could erase data. Magnets near a CRT monitor can distort the images on the screen. CRT monitors, speakers, motors, and generators contain magnets (keep sensitive components away from these devices). Solid state storage devices (such as RAM or flash drives) are not affected by magnetic fields.

Difference Between Online and Offline

Online the battery is continually charged, the PC draws its power directly from the battery. The PC never gets power from the wall outlet. Offline the PC draws power through the UPS, from the wall outlet until the current drops below a certain point. At which point this connection is broken and the system starts pulling power from the battery itself. Cost is about $100.

Radio Frequency Interference (RFI)

Radio Frequency Interference (RFI) is interference on the radio channel used by wireless networking devices. RFI can be caused by nearby wireless devices using the same channel, cordless phones, or microwave ovens. Wireless networks that use the 2.4 GHz frequency range (801.11b and 802.11g) are susceptible to RFI. RFI can be reduced by using a wireless networking standard that operates in the 5.75 GHz range, or by using a different channel for wireless devices.

UPS Size

UPS size is measured by the volt-amp (VA) rating. The capacity of the UPS determines the number of devices and how long the devices can run when power is interrupted. When purchasing a UPS, purchase one with enough battery power to only power critical devices such as the computer and a single monitor. To reduce the amount of power required by the UPS, do not plug non-critical devices in to the UPS. Laser printers require more power than most UPS systems are capable of providing. For this reason, you should not connect a laser printer to a UPS. If you must provide power to a laser printer, get a dedicated UPS for that device.

Cleaning Your Computer (Cont'd):

Use caution with liquid-based cleansers. Use small amounts and always apply cleaning solutions to cloths and cleaning instruments, never directly to component surfaces. Dust buildup inside a computer acts as an insulator for internal components, trapping heat and preventing adequate cooling of components. Use: Compressed air to blow dust off A non-static vacuum to remove dust A natural bristle paintbrush to wipe components off

UPS Configuration

You usually need to configure the following settings when working with UPS software: Time to wait before sending a warning to clients Time to wait before beginning a shutdown Name of programs or commands to run during shutdown In addition to providing power when the power is lost, most UPS systems also condition the line and remove power spikes and sags. Most UPS's sound an alarm when the AC power is lost. This alarm continues until AC power is restored, although many UPS's have a switch to mute the alarm.

Interference

a signal that corrupts or destroys regular signals. Interference affects signals used by two devices to communicate on a network. Listed below are two types of interference that affect computer networks.

Standby Power Supply (SPS)

an offline device that switches over to provide power when an under voltage occurs. If the switchover is not fast enough, the computer loses power.

Uninterruptible Power Supply (UPS)

an online device that is constantly providing battery power to the computer and being recharged by the wall outlet. There are two types of UPS systems: An online UPS constantly powers the computer from the battery. An offline UPS powers the computer from the wall power. When the power fails, a switch inside the UPS switches to power the computer from the battery. This is the most common form of UPS.

Line conditioner

modifies the power signal to remove noise and create a smooth alternating current (AC) current.

Disadvantage of Offline UPS:

when the power drops below 80v and switching takes over from the wall current to the battery there is a tiny millisecond delay that the power is turned off basically for just a few milliseconds while the current is switched over.