Hint in Software

Maker Code 39 Extended in Software Hint

The CompTIA A+ 220-602 (IT Technician) exam will typically refer to the power supply using the abbreviation PSU (power supply unit) or the acronym FRU ( eld replaceable unit) FRU can describe any component that would be replaced in the eld by a technician

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Let s assume that you ve found a variance in the 12 Volt range that explains your client s system lockups You know that power supplies aren t user-serviceable components you don t x them; you replace them as a unit so it s time to replace her power supply Next to the motherboard, the

power supply is the most time-consuming component to replace, simply because of all those wires! Nonetheless, replacing it is a simple operation, as described in the following sections

At the end of this lab, you ll be able to Determine the total wattage requirements of the system and select the proper power supply Replace a power supply

The materials you need for this lab are A non-production PC computer system A working PC with an ATX power supply (optional) A Phillips-head screwdriver A labeled container for holding screws

One of the areas where PC manufacturers cut corners on lower-end systems is power supplies High-end systems typically come with higher-wattage power supplies, whereas entry-level PCs typically have lower-wattage power supplies This might not be evident until you add power-hungry components to the system, placing a heavier load on the power supply and causing an early failure In the following steps, you ll determine the wattage of the power supply on your system, calculate the power usage of your PC, and then remove and reinstall the power supply Step 1 To nd out what the wattage rating of your power supply is, look at the label on the power supply (see Figure 7-1)

Find the similar label on your power supply, and locate the watts rating If you don t see a clear wattage rating, as shown in Figure 7-1, or something less evident, like the smaller 430 W marking on the label, the power supply rating may be hidden in the model number, which, in this example, is Neo HE430

All power supplies have a wattage rating If it is not apparent on the power supply itself, search the Internet, using the model number for reference

What is the wattage of your power supply __________________ Step 2 When it comes time to replace a power supply, don t skimp on the wattage! Modern power supplies typically range from 300 watts to 1000 watts or more Three hundred-watt power supplies are the bare minimum you would use on a system that has only a few installed components (such as a single hard drive and CD- or DVD-media drive), while the 1000-watt models are usually found on server systems that have multiple hard drives (such as a Redundant Array of Inexpensive Disks [RAID] array), multiple processors, or other power-hungry components Many gaming systems with high-performance graphics, dual-core processors, and Serial Advanced Technology Attachment (SATA) RAID con gurations will use PSUs that provide 550 to 650 watts to meet these systems power requirements As a general rule, get the highest-wattage replacement you can afford while maintaining compatibility with your system Remember, the system will only draw the current it requires, so you will never damage a system by installing a higher-wattage power supply

Never replace a PC s power supply with one of lower wattage!

Use Table 7-1 to calculate the overall wattage needed for your system Add the numbers for each component, and determine the lowest and highest wattage requirements If the highest total exceeds the power-supply wattage rating, you may run into problems When selecting a new power supply, you should multiply the load by a factor of 15 The multiplier provides a safety factor and allows the power supply to run more ef ciently A power supply is more ef cient at 30 to 70 percent of its full capacity rating Thus, a 450-watt PSU works best when only 135 to 315 watts are being used What wattage is appropriate for your system _______________________