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

Summary: Learn how to run a self-test diagnostic on the power supply unit of a Dell desktop or all-in-one computer. Built-in Self Test (BIST) helps determine if the power supply unit is working. ...

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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Instructions

Dell Inspiron, XPS, OptiPlex, Precision, and Vostro desktops come with a handy built-in self-test (BIST) feature for the power supply unit (PSU). This feature, along with the LED indicator on the PSU, helps you check if everything's working fine.

If your PSU is not delivering enough power, your computer cannot not turn on.

NOTE: Some older models of Dell Inspiron, XPS, and Vostro desktops might not have this built-in self-test. But do not worry, you can still learn how to troubleshoot and fix power issues.

Common reasons for power supply failure are:

  • Faulty or damaged power cable
  • Non-working power outlet
  • Faulty power strip or surge protector
  • Faulty power supply unit

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

Look for the BIST on the back panel of your desktop, next to the power cable connector. On some smaller chassis types, you must 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

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

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

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

BIST button on the power supply of a desktop
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

power supply without the BIST 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?

Running a Self-Test on Your PSU with a Button

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

Running a Self-Test on Your PSU without a Button

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

Additional Information

Tutorial on Dell’s Built In Self Test for power supplies if No Power

Duration: 02:56
Closed captions: This video is available in multiple languages. Click the Closed Caption icon and select the language that you want.

Affected Products

Alienware, Dell All-in-One, Dell Pro All-in-One, Dell Pro Max Micro, Dell Pro Max Slim, Dell Pro Max Tower, Dell Pro Micro, Dell Pro Slim, Dell Pro Tower, Dell Slim, Dell Tower, Inspiron, Legacy Desktop Models, OptiPlex, Vostro, XPS, G Series , Fixed Workstations, Dell Pro Max Micro XE FCM2250, Dell Pro Max Slim XE FCS1250, Dell Pro Max Tower T2 XE FCT2250, Dell Pro Micro Plus XE QBM1250, Dell Pro Slim Plus XE5 QBS1250, Dell Pro Tower Plus XE5 QBT1250 ...
Article Properties
Article Number: 000125179
Article Type: How To
Last Modified: 20 Jun 2025
Version:  13
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