How to Run a Power Supply Unit Self-Test On a Dell Desktop or All-in-One Computer

Dell Inspiron, XPS, OptiPlex, Precision, and Vostro desktops include a power supply with a built-in self-test (BIST) feature that helps check the power supply unit health (PSU). The LED indicator on the power supply unit helps identify if it is faulty.

If the power supply unit does not deliver sufficient power that your computer needs, it will not turn on.

Some causes for a power supply unit failure are:

• The power cable is faulty or damaged.
• The power outlet is not working.
• The power strip or surge protector is faulty.
• The power supply unit is faulty.

How to identify if my Dell desktop has a power supply unit with built-in self-test?

The power supply built-in self-test is found on the back panel of the desktop, next to the power cable connector (on some smaller chassis types, you may be required to remove the computer cover to see the BIST on the side of the PSU).

Examples of a power supply unit with the built-in self-test button

Figure 1: Example of a BIST button on the power supply of a desktop computer.

Figure 2: Second example of a BIST button on the power supply of a desktop computer.

Figure 3: Third example of a BIST button on the power supply of a desktop computer.

Figure 4: Fourth example of a BIST button on the power supply of a desktop computer.

Examples of a power supply unit without the built-in self-test button

Figure 5: Example of a power supply without the BIST button.

How to use the built-in self-test to diagnose power supply issues?

How to run self-test using the button on the PSU

1. Turn off the computer.
2. Press the BIST button and verify if the LED turns on.
3. The LED must be solid and not flickering or flashing. The power supply fan turns on. If the PSU fan does not spin correctly, consider the built-in self-test as failed even if the LED lights up.
   1. If the BIST LED turns on, the power supply is delivering power to the computer.
   2. If the BIST LED does not turn on or the PSU fan does not spin correctly, the power supply is not delivering power to the computer. Disconnect and reconnect the power cable to computer and try again. If the BIST LED does not turn on, contact Dell Technical Support for repair options.

How to run self-test without the button on the PSU

1. Turn off the computer.
2. Disconnect the power cable from the PSU, and wait for 15 to 20 seconds.
3. After 15 to 20 seconds, connect the power cable to the computer.
4. The LED light turns on for 3 seconds and then turns off.
   1. If the BIST LED turns on, the power supply is delivering power to the computer.
   2. If the BIST LED does not turn on or the PSU fan does not spin correctly, the power supply is not delivering power to the computer. Disconnect and reconnect the power cable to computer and try again. If the BIST LED does not turn on, contact Dell Technical Support for repair options.

Recommended Articles

Here are some recommended articles related to this topic that might be of interest to you.

• How to Troubleshoot Power Issue on a Dell Desktop or All-in-One
• Resolve No Power, No POST, No Boot or No Video issues with your Dell Computer
• How to Troubleshoot the Power Supply Unit (PSU) of a Dell Desktop Computer