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© Galatea Training Services Limited, 2004

Core Hardware Domain 3.0 - 1

V1.0 A+ Module – CHD3.PPT

A+ ModuleCore Hardware Service Technician

Domain 3.0Preventative Maintenance, Safety,

and Environmental Issues




Preventive Maintenance

CleaningPreventive maintenance proceduresPower-line protection




CleaningCleaning is a major part of keeping a computer

system healthy:Use a lint-free soft cloth (chamois) for cleaningthe plastic outer-surfaces of the systemOuter-surface cleaning can be accomplishedwith a simple soap-and water solution, followedby a clear water rinseCleaning should be followed by the applicationof an anti-static spray or anti-static solution




Preventive MaintenanceProcedures

Computer equipment is susceptible tofailures caused by: Dust buildup Rough handling Extremes in temperature




Heat BuildupCheck for other sources of heat buildup around

the computer and its peripherals. Thesesources include the following:Direct sunlight from an outside windowLocations of portable heaters in the winterPapers/books piled up around the equipmentComputer furniture design and placement(creating a lack of free air space around thecomputer)




Protecting MonitorsThe preventive maintenance associated with monitors

consists of:Periodic cleaning, dusting, and good commonsensepractices around the monitor.Aerosol sprays, solvents, and commercial cleanersshould be avoided because they can damage thescreen and cabinet.A simple cleaning solution is fine for cleaning themonitorMake sure that the monitor’s power chord isdisconnected from any power source before washingThe monitor’s screen should be dried with a soft clothafter rinsing




Caution Areas Inside the Monitor




Caring for LCD DisplaysThe screen should be cleaned periodically with aglass cleaner and a soft, lint-free clothSpray the cleaner on the cloth and then wipe thescreenNever spray the cleaner directly on the screenAvoid scratching the surface of the screenTake care to remove any liquid droplets from thescreen because they can cause permanent stainingAfter cleaning, allow 30 minutes for complete drying




Protecting Hard-Disk DrivesRough handling is responsible for more hard-disk drive damage than any other factorThe drive should never be moved while you canstill hear its disks spinningIf a hard-disk drive is to be transported orshipped, make sure to pack it properlyAt no time should the hard drive’s housing,which protects the platters, be removed in openair.




Proper Packing of aHard Drive for Shipment




Protecting Removable Media Drives

Removable cartridges or disks can be adverselyaffected by:Extremes in temperatureExposure to magnetic and electromagneticfieldsBendingAirborne particles that can lead to informationloss




Maintaining Removable Media Drives

Cleaning kits are available for:Floppy drivesCD/DVD drivesTape drives




Cleaning the R/W Headson a Floppy Drive




Protecting Input Devices

Input peripherals generally require verylittle preventive maintenanceAn occasional dusting and cleaningshould be all that’s required




Cleaning the Keyboard




Cleaning the Rollersin a Trackball Mouse




Power-Line ProtectionTypical power-supply variations fall into two categories:

Transients—overvoltage conditions that can beclassified as spikes (measured in nanoseconds) or assurges (measured in milliseconds)Sags—undervoltage conditions that include voltagesags and brownouts. A voltage sag typically lasts onlya few milliseconds, whereas a brownout can last for aprotracted period of time




Surge Suppressers

There are two factors to consider when choosinga surge suppresser:Clamping speed—how quickly the protectivecircuitry reacts to changes in the incomingpower level and attempts to limit the changeClamping voltage—the designated voltage levelthat the device will attempt to maintain




Uninterruptible Power Supplies

Uninterruptible Power Supplies (UPS) arebattery-based systems that monitor theincoming power and kick-in whenunacceptable variations occur in thepower sourceCan be either a standby power system(offline) or an active power system(online)




UPS Systems




Connecting the UPS in the System




System Protection

Electrostatic dischargeProtection during storageDisposal proceduresAvoiding high-voltage hazardsAvoiding laser and burn hazards




Electrostatic Discharge

An electrostatic discharge (ESD) is the mostsevere form of electromagnetic interference(EMI)The most common causes of ESD are:– Moving people– Improper grounding– Unshielded cables– Poor connections– Moving machines– Low humidity (hot and dry conditions)




MOS Handling Techniques

Metal oxide semiconductor (MOS) devicesare sensitive to voltage spikes and staticelectricity discharges. Therefore youshould:Use a grounding strapUse antistatic mats




Typical Antistatic Devices




Discharging Throughthe Power-Supply Unit




Power Transmission System




Protection During Storage

The best storage option for mostcomputer equipment is the originalmanufacturer’s boxIf the original boxes and packing materialsare not available, make sure to use sturdycartons and cushion the equipment wellon all sides




Disposal ProceduresMost computer components contain some level of

hazardous substances:Printed circuit boards consist of plastics, preciousmetals, fiberglass, arsenic, silicon, gallium, and leadCRTs contain glass, metal, plastics, lead, barium, andrare earth metalsBatteries from portable systems can contain lead,cadmium, lithium, alkaline manganese, and mercury




Avoiding High-Voltage Hazards

In most IBM-compatibles, there are only twopotentially dangerous areas for high-voltage hazards: Inside the CRT display Inside the power-supply unit




Avoiding Laser and BurnHazards

Laser printers contain many hazardousareas:The laser light is a hazard to eyesightThe fuser area is a burn hazardThe power supplies are shock hazards

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