What Is the Power Supply?

Introduction: What Is the Power Supply?

  • The hardware component that supplies power to the motherboard and it's numerous components.
  • A PSU is labeled with a VA rating, 1 VA= 1 watt.
  • The number of watts a power supply has is the amount of electrical power the power supply will provide to the motherboard.
  • The 80+ Bronze/Silver/Gold rating system- A PSUs level of efficiency for power conversion at power levels of 20%, 50%, or 100%.
    • Generally Speaking, the higher the PSU is on the rating system (80+ standard being the lowest and 80+ platinum or 80+ titanium being the highest) the more efficient it will be at supplying components both on and off the motherboard with power. Along with high efficiency, you also get less heat produced, increasing fault tolerance.

Step 1: Pieces Parts

  • ATX 24 pin connector- The standard motherboard connector that supplies power to the motherboard. The following are what each color cable on the 24 pin connector does in terms of power supply.
    • Orange- Measures as 3.34v, and provides power to newer CPU’s as well as some types of memory, AGP video cards, and other circuits. Pins 1, 2 and 12
    • Black- Measures as 0v and grounds the PC's electrical system. Pins 3, 5, 7, 15, 17, 18, 19, and 24.
    • Blue- Measures as -11.83v, and provides power to serial ports that require -12 or +12 v. Just pin 14.
    • Yellow- Measures as 12.03v, and provides power to serial ports that require -12 or +12 v. Pins 10 and 11.
    • Purple- Measures as VSB 5.06v, and is used to run the motherboard and CPU directly. Just pin 9.
    • Gray- Measures as 5.09v, and serves as a power OK signal. Just pin 8.
    • Green- Measures as 0.05v, serves as a PS_ON# signal. Just pin 16.
    • Red- Measures as 5.11v, and serves the same purpose as both the grey and purple cables. Pins 4, 6, 21, 22, and 23.
    • White- Measures as -4.96v, and provides power to the floppy controllers and circuits that use ISA bus cards. Just pin 20.
  • ATX 12v connector- This 4-pin connector is used to provide electrical current to the system CPU and must be installed on the motherboard. The following are the different pins and their corresponding information.
    1. Black cable- Serves as a ground measuring at 0v
    2. Black cable- Serves as a ground measuring at 0v
    3. Yellow cable- Measures at +12v
    4. Yellow cable- Measures at +12v
  • Standard 4 pin- It was used on older computers for floppy drives and hard disks, now it provides to all sorts of things from add-on fans, extra video card power, supplemental motherboard power, and case lighting. The following are the pins on the cable and their corresponding information.
    1. Yellow cable- Measures to be +12v
    2. Black cable- Serves as a ground measuring at 0v
    3. Black cable- Serves as a ground measuring at 0v
    4. Yellow cable- Measures to be +5v
  • SATA power connection- Was introduced as a replacement for ATA cables with a new advanced design. It replaces the old 4 pin peripheral cable listed above, thus serving the same purpose but with +3.3v pins implemented along with the standard +12v and +5v cables that already came with the 4 pin peripheral cable.

Step 2: Maintenance

  • Physical care/ maintenance
    • Tools/equipment for maintenance
      • Interchangeable power wall plug in case of faulty plug
      • Compressed air for fan dusting
      • Zip-ties for cable management
      • Voltage multi-meter to measure proper power distribution
      • Surge protectors prevent unwanted power abnormalities in a power strip from getting to the computer.
  • Software care/ maintenance
    • Software or utilities device for monitoring and optimizing the device
      • There is no optimizing a power supply in terms of overclocking or specific settings, you simply plug it into your motherboard and other components. This is why the all maintenance for a power supply is for the most part, done on the physical level. However, online power supply calculators can be used to help identify what type of PSU will be best compatible for the components in your PC (a video demonstration will be shown at the end).

Step 3: Diagnostics, Troubleshooting, and Repair of the Power Surge

  • The power surge.
    • A power surge is an abnormal fluctuation in voltage or current and is the most common form of error within a PSU. This can result in a fried components and ports on the motherboard, along with failure in the PSU itself and its cables resulting temporary low power or no power. This in turn means that the computer will not function as a result of lack of power and damaged devices/ ports.
      • Possible power surge causes include lightning, circuit failure, power outage, or excessive power usage on the same power line as the PSU.
    • Troubleshooting and repairing a power surge
      • Chances are that you cant repair any power surge damaged devices other than finding a replacement device, however here are a few preventative measures to avoid a power surge.
        • Preventative measures
          • Use surge protectors on your power strips to block or short unwanted voltages from entering the PC.
          • Use a High rated VA PSU because they can tolerate higher voltage spikes.
          • UPS's provide a fallback measure in terms of power for the devices in the event of power failure.
      • Troubleshooting for PSU failure
        • Check the motherboard indicator light, if it is not lit you know that you have power error.
        • Identify if non-motherboard devices are working, primarily if the disk drive, fans, or LED's are functioning.
        • Once you have identified your error as a power supply failure, either change the outlet the power supply is plugged into, and then attempt to turn on the PC. If the device remains the same replace the wall cable used to plug the PSU into the outlet and attempt to turn the PC on again. If the issue still remains use a spare PSU to test if a new PSU is required. Chances are if you've made it this far, a new PSU will be required, however if their still is no change, check the power ports on the motherboard using a multi-meter to identify any faulty ports. If there is a damaged motherboard port you may need to purchase a new motherboard in total.

Step 4: PSU Calculator Run Through Demonstration

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    Nice introduction to power supplies. I use these to build bench power supplies all the time.