Saturday, December 11, 2010

A Word About PC Power Supplies

All were shocked when there's a loud “pop” sound, followed by bad smell – something was burned. Later we discovered that it was the power supply of a desktop PC.

1) How do we know it's the power supply?

Actually, by appearance, could tell for sure it's the power supply. However, I went through the investigation with the following steps: Ask, See, Assume, Smell, Test

Ask – ask the user what's happened when the PC was suddenly down. He plugged his mobile phone to the computer through a USB cable. After a few seconds, the tragedy! Well, … don't be quick to blame the user.

See – open the case cover, sight inspection; I'll first check the chips and the capacitors. Any sign of being burned? No...

Assume – this may be the most difficult part, as it takes a lot of experience to make proper assumptions. I'll suspect, the front panel circuit could be short-circuit, the front panel USB port is bad, power supply dead.

Smell – very interesting part, sounds very “low tech” way of troubleshooting. But, it works very well sometimes. I smell the back of the PC, the burned smell is strong!

Test – Get a new power supply, replace the suspected bad one and test it. The computer is back normal!

More lessons:

2) Why the power supply will burn?

Well, among the many parts of a computer, the power supply is one of the easiest to fail. It's always wise to invest more for a better power supply. Avoid using a bare-bone case with a bare-bone power supply. The ventilation of a bare-bone case is bad. When dust accumulated inside the computer, the situation can easily go ugly. Besides, bare-bone power supply is more vulnerable to failure because of the accumulation of heat and dust as well as lower loading capacity.

If you're a home user, and play a lot games with high-demanding graphics, ventilation is especially important. A sizable case, with a power supply capacity high enough is a must. A normal size power, not a bare-bone power is necessary.

3) Which power supply model is right for my computer?

Some companies provide free calculators to let you estimate the power supply you need, just one example:

A test of this service, I select one Core i3 540, 2xDDR3 RAM, one SATA HDD and one DVDRW, with 90% CPU utilization and loading. The result is I was recommended to have 208W PSU. A 350W power supply will be good enough.

Another test, I select a Core i7 880, 2xDDR3 RAM, 2 SATA HDD and one DVDRW, with a GeForce GTX 480 display card, with 90% CPU utilization and loading. Press “Calculate”, a much higher recommended value given – 479W. A 350W power supply will definitely not enough. I need to go for a maybe 550W power supply!

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