This article may have been automatically translated. If you have any feedback regarding its quality, please let us know using the form at the bottom of this page. A faulty power supply can cause a system failure in one of two ways. It may not provide power to the system at all or it may not provide sufficient voltages and/or current to the various components of the desktop computer. The following step by step checklist helps identify if the power supply unit is working correctly.
- Are the LED lights turned on? Check the power button, diagnostic LEDs, and HDD activity LED.
- Are there other signs of power such as fan spinning or disk drive activity?
- Is the power cord plugged into the back of the system and into a known working power source? It is important to bypass any power strips, surge protectors or UPS units by making sure the power cord is plugged directly into a known good wall outlet.
- Is the voltage selector correctly set for local power? Some power supplies are auto-switching and do not have a physical switch. For those that do, make sure the power cord is unplugged and flip the switch back and forth; again making sure it is set to the proper voltage. Plug the power cord in and test.
- If there is still no sign of power, the next step is to isolate the power supply as much as possible. Make sure the power cord is unplugged and disconnect the power leads from all devices except the motherboard.
- Any power leads to the motherboard should be reseated to ensure a good connection.
- Remove memory, expansion cards and disk drive data cables to insure they are not causing the failure. These components would need to be removed later to complete no POST troubleshooting anyway if the power supply is not at fault.
- If appropriate to the system model, test the I/O panel.
- If there are still no signs of power at this point, it is most likely the power supply is non-functional. If there are indications of power, continue troubleshooting to isolate the failed component.
- Bypass any power strips, surge protectors or UPS units by making sure the power cord is plugged directly into a known good outlet.
- If the system fails to power up correctly and attempts POST, the next step is to isolate the power supply as much as possible. Make sure the power cord is unplugged and disconnect the power leads from all devices except the motherboard.
- Any power leads to the motherboard should be reseated to ensure a good connection.
- Remove memory, expansion cards and disk drive data cables to ensure they are not causing the failure. These components will need to be removed later to complete no POST troubleshooting anyway if the power supply is not at fault.
- If the system fails still fails to power up correctly and attempt POST at this point, it is most likely the power supply is non-functional and should be replaced. If however, the power LED is solid amber, the failure could potentially be the motherboard and Technical Support involvement may be required.
- If there are indications of power, continue troubleshooting to isolate the failed component. Our articles Computer Does not Turn on or go Into Windows or Resolve No Power, No POST, No Boot or No Video issues with your Dell Computer can provide additional troubleshooting to help.
Dell Inspiron, XPS, OptiPlex, Precision and Vostro desktop systems include a power supply with a built in self-test (BIST) feature that helps diagnose the health of the power supply unit. The LED indicator on the PSU helps identify if the power issue is caused by the power supply unit. Note: Certain older models of Dell Inspiron, XPS, and Vostro desktop systems may not be equipped with a PSU built-in self test. To learn more, see the Dell knowledge base article How to Run a Power Supply Unit Self Test On a Dell Desktop or All-in-One Computer. How to run the self-test using the button on the PSU - Turn off the computer.
- Press the BIST button on the computer and check whether the LED lights up.
- The light should be solid on not flickering or flashing and the power supply fan should also turn on to speed. If the fan is not spinning up properly this should be considered a BIST failure even if the LED lights up.
- If the built-in self-test LED turns on, then the power supply unit is able to deliver power to the system board.
- If the BIST LED does not light up, then the power supply is not able to deliver power to the system board and could be caused by any component connected to the power supply or the power supply itself. The next step would be to isolate the source of the power failure by disconnecting parts from the PSU, see the Dell knowledge base article Resolve No Power, No POST, No Boot or No Video issues with your Dell Computer.
How to run the self-test without the button on the PSU - Turn off the computer.
- Disconnect the power cord from the PSU, and wait for 15 seconds.
- After 15 seconds, connect the power cord back to the PSU.
- The LED light should stay on for 3 seconds and then turn off.
- If the built-in self-test LED turns on, then the power supply unit is able to deliver power to the system board.
- If the BIST LED does not light up, then the power supply is not able to deliver power to the system board and could be caused by any component connected to the power supply or the power supply itself. The next step would be to isolate the source of the power failure by disconnecting parts from the PSU, see the Dell knowledge base article Resolve No Power, No POST, No Boot or No Video issues with your Dell Computer.
General information and troubleshooting articles can be found on the AC Adaptor support page. Desktops & All-in-Ones, Laptops All fields are required unless marked otherwise. Thank you for your feedback. Sorry, our feedback system is currently down. Please try again later. Comments cannot contain these special characters: <>()\ If the power indications are normal, but there is never any video that is seen on the computer's display during the startup process? This probably indicates a No Video issue. NOTE: For Desktop computers - Remember that the monitor has a separate power supply. Make sure the monitor has a power LED indicator showing that it is powered on. NOTE: Certain Dell All-in-One PCs can be connected to an external monitor via VGA, HDMI, or DisplayPort connectors. This feature may vary across different models. Refer to the User Manual of your Dell PC. Troubleshooting a No Video issue: | Problem Description | Suggested Resolution | The desktop computer is in a normal on condition.
The diagnostic lights are not lit after the computer successfully boots to the operating system but there is no display showing. | - Ensure that the display is connected to the correct port and powered on.
- Ensure that the display data cable is not damaged and replace if necessary.
- Ensure that the correct Input Source on the display is correctly selected.
- Remove the data cable from the system. A Self-Test box should appear on the display.
- If the Self-Test box does not appear on the display, replace the display with a verified working unit.
- If there is still no display showing, check if video was shown during the POST routine.
- If video was shown during POST, the display or graphics driver could be the cause.
- Restart the system into Safe Mode. To load Safe Mode, press and hold the F8 key as your system restarts.
- This loads the Advanced Boot Menu. Select Safe Mode. Install the current versions of the display and graphics card drivers. Restart the system, and check for video.
- If available, replace the graphics card with a verified working card.
- If both graphics card and monitor work ok on another PC, then contact technical support to resolve the problem.
| NOTE: For Notebooks, press and hold the <Fn> key and then press the power button. This starts the preboot testing and will launch the ePSA diagnostics. The ePSA's will test your video with a series of patterns. Duration: 01:46
Closed captions: English only If they look fine, but you want to test more? You can respond to the video test by pressing the letter <N> and ePSA will then launch the LCD BIST test. If you have a no video issue? You can either run the <Fn+Power> keyboard shortcut to enter the ePSAs or <D+Power> keyboard shortcut to run the LCD BIST from POST. Duration: 00:24
Closed captions: English only NOTE: Two new diagnostic BIST tests have been built into the Dell family of notebooks, starting with the Latitude XX90 generation of systems. | M-BIST - Built-in Motherboard Self-Test tool | L-BIST - Built-in LCD Power Rail Self-Test tool. | | Evaluates the health of the motherboard | Checks if the motherboard supplies power to the LCD. | | M-BIST is designed to operate even if there is no video, no fan, or no hard drive spin-up (new mainboard diagnostic). These symptoms are typically described as No Power, No Video, or Dead System. | L-BIST is designed to test when seeing the symptom of No Video. | Press and hold the M key and the Power button down simultaneously: - If an error is detected the Battery status LED lights up Amber and you need to contact us
- If the Battery status LED does not light up, then no fault is detected with the motherboard
| Press and hold the Power button down: - If there is no display and an error is detected. The Battery status LED will flash 2 x Amber and 8 x White, and you need to contact us
- If there is no display and the Battery status LED does not light up, then no fault is detected with the motherboard
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