Computer Info –
No Meeting This Week
The next meeting will be February 19th.
Power Supplies
(Info from Smart Computing – March, 2003 issue)
Many people think that the measure of a computer’s quality is dependent upon it’s CPU chip. While many understand that the real driving force behind a stable, powerful computer is a rugged power supply. – others choose a computer with an inadequate or lower quality power supply and then suffer a myriad of problems.
A computer can’t simply use the electricity that comes out of your wall outlet. Standard household electricity is AC (alternating current) and your computer uses DC (direct current) to power its internal devices.
Your power supply converts standard electricity operating at 60Hz into a higher frequency current. This makes it easier for the transformers in the power supply to perform a voltage step-down. Stepping down the voltage entails transforming the 100 volt current into a series of lower voltages. These are typically 12V, 5V and 3.3V which are dispensed to your computer’s components through a group of connectors called rails. Hard drives, fans, and optical drives typically use 12 volts, your CPU and other electronic circuitry generally use the 5V and 3.3V rails.
Power supplies vary in quality and performance. Most of today’s PCs use the ATX (Advanced Technology Extended) style power supply with older models of computers using the AT (Advanced Technology) style. If you are not sure what type of power supply your computer has, check for a label that indicates the type. When you buy a new computer, you will want to make sure that the power supply it ships with is adequate for your current, as well as future, needs.
The first feature to look for in a quality power supply is adequate cooling. As the power supply’s transformers step down the voltage, they create a large amount of heat that needs to be properly dissipated. Most ATX power supplies have at least one fan, and high performance power supplies often have two. Without adequate ventilation, your power supply can quickly overheat your computer, affecting performance and even damaging components.
Another important consideration is the load your power supply can carry. Power supply capacities are rated in watts, calculated by multiplying voltage by amps. A common rating is around 250 watts, with high-end supplies topping out at more than 500 watts.
Also, a good power supply uses quality components. How can you tell? The best yardstick to use is price and reputation. A $20 power supply will probably be using inferior components compared to a power supply selling for $100.
You should not be using more than 50% of your power supply’s capacity. If a power supply is operating close to its peak output, it will generate more damaging heat and wear out at a faster rate.
Computers with faulty power supplies may exhibit a variety of symptoms, the most common are mysterious reboots of your operating system or a failing hardware device.
If you overload your power supply with a new component (such as installing a second hard drive or CD-RW) and then you attempt to reboot your computer only to see it fail -- remove the new drive, and the computer boots properly. Your first instinct is that the drive is defective, yet the true culprit is a lack of adequate power. Another symptom of an overloaded or failing power supply is one or more components suffer from degraded performance. In this case, a component may function, but because it’s not receiving enough wattage, its performance drops. This is common with many of today’s high-powered graphics cards. These cards draw power from your motherboard’s AGP slot but also draw additional power directly from the power supply.
Overheating is another common problem with power supplies. Overheating can cause surges on the rails, damaging your computer’s components. Also this added heat can cause your processor to overheat, leading to the infamous BSOD (Blue Screen of Death).
The easiest way to avoid problems is by choosing a reputable power supply.
Dell and Power Supplies
(Info from Smart Computing – March, 2003 issue)
Most of today’s computer manufacturers use the standardized ATX format for their computer power supply units. But, not Dell!
Starting in September, 1998, Dell started a program that has created and continues to create problems for users seeking to replace or upgrade their Dell computers.
At first glance, both the power supplies and the motherboards in the Dimension line of desktops look like normal ATX-style equipment. The power connectors are the familiar keyed connectors we’ve grown accustomed to, as are the 12V connectors used for fans and other devices.
But appearances are deceiving. For reasons known only to Dell, the company decided to make alterations to the wiring harness, as well as the motherboards they ship. If you examine closely the wiring that plugs into the connectors, you will find that Dell has reversed several wires.
If you use a Dell brand power supply and motherboard, you will not have any problem, as the Dell motherboards expect this wiring arrangement. However, if you try to replace your Dell power supply with a non-Dell replacement, you may severely damage your motherboard because the replacement power supply would send the wrong currents to your system. Also, if you replace your Dell motherboard with a non-Dell approved motherboard, you will probably end up with a damaged motherboard. In either case, you also risk damaging the power supply, and some users have reported experiencing fires in their computers when using a non-Dell motherboard or power supply.
So, since Dell is using proprietary hardware, if you find a need to replace your power supply or motherboard in your Dell computer, be sure that you use either a Dell brand power or one that is compatible.