Print
login Account
Search

Troubleshooting power issues - Desktops

Troubleshooting power issues assumes there is no indication of power. The system has worked in the past but now fails with one of the two symptoms indicated below:

Select your symptom. If it does not appear in the following list, continue to the Need more help? section.

System will not power on
System powers off unexpectedly

System will not power on

There is no indication of any power, the power-on indicator is not on, and the power supply fan is not running.

  1. Check the power cord and on/off switch connector for proper installation.
  2. Ensure that the 115/230 voltage selector switch on the back of the system is set to the correct voltage for your region. If you change the switch position, make sure to unplug the computer first.

    Warning: Applying 230 volts to a system set at 115 will ruin the power supply.


voltage selector switch

  1. Make sure power is available. Make direct connections to energized wall sockets. Remove any surge protectors and power strips. Swap power cords with the monitor if possible.
  2. Perform a power supply reset by unplugging the power cord, then press the power button in and hold for 10 seconds. Reattach the power cord and try to power on the computer.
  3. Check the power supply diagnostic LED indications. Some newer power supplies are equipped with LEDs to indicate power supply and system board diagnostic conditions. Refer to the table below, observing the state of the Power LED on the front of the computer and the 2 diagnostic LEDs on the power supply to determine the condition.

ThinkCentre power supply LED indications
Power LEDGreen
diagnostic LED
Yellow
diagnostic LED
Action
ON ON OFF This is the normal condition of the LEDs when the power is OK.
OFF OFF OFF Make sure the power cord is attached to a working electrical outlet.
If the electrical outlet is OK, replace the power supply.
OFF
(after the power button has been pressed)
ON OFF Replace the system board
ON ON ON Replace the power supply

  1. Check that the power switch is mounted to the chassis or to the fan/speaker/power switch assembly.
    • The switch should be securely attached to the chassis. If the switch has become dislodged, it can be pushed back into position.
  2. Check to see if the machine boots with the cover off, using a pencil to press the power switch.
    • Some power switches connect directly to the system board. Make sure the wire lead from the power switch is firmly connected to the system board.
    • If possible, test the switch for continuity when depressed with an ohm meter.
  3. Reseat the connector from the power supply to the system board.
  4. Disconnect all drives and remove all adapters and memory, leaving only the processor, system board, and the power supply system board connector connected.
  5. Reseat the system board and/or riser adapter card as applicable.

11. If the machine is being professionally serviced, make sure all part numbers are correct for the machine.

If you are still experiencing problems, continue to the Need more help? section.

Back to top

 

System powers off unexpectedly

The system shuts off unexpectedly by itself. The power indicator light is not flashing.

  1. Ensure that the 115/230 voltage selector switch on the back of the system is set to the correct voltage for your region. If you change the switch position, make sure to unplug the computer first.

    Warning: Applying 230 volts to a system set at 115 will ruin the power supply.

voltage selector switch

  1. Remove any surge protectors and power strips. Swap power cords with the monitor if possible.
  2. Check all external cord connections for possible loose or broken connections or fasteners.
  3. Test the machine for an extended period while booted to the System Configuration Utility. When you power on the computer, press the F1 to go to BIOS setup; you will be taken to the System Configuration Utility. If you do not experience any power issues while in the System Configuration Utility, your problem is probably being caused by software, not hardware, issues. Contact your software vendors for additional information.
  4. Remove the system cover and verify the power supply fan and processor fan (if installed) work. The processor fan may work intermittently depending on processor temperature. The power supply fan should run continuously.
  5. Disconnect any additional drives (such as serial or parallel hard drives, CD-ROM or DVD drives, PCI or PCI-Express adapters, or memory) that were added recently. The addition of new drive(s) or other power consuming devices could be causing the system to power off. If a new drive(s) did cause the problem, it may be defective or incompatible with the system.
  6. Run the latest version of PC diagnostics available for your system.
  7. Ensure that the latest BIOS code is installed.
  8. Set CMOS to its default settings.
    1. Power on the system
    2. Press the F1 key at the screen prompt.
    3. Select Load defaults and press Enter.
    4. Confirm the selection by selecting OK and press Enter.
    5. Save the settings and exit.
  9. Reseat the memory.
  10. If these steps have not solved your problem, refer to "Need more help?"
Back to top


Need more help?
Please select one of the following options for further assistance:

Troubleshooting booting issues
Submit a technical question
Contact your local technical Support Center
Check warranty status and upgrade
Return to NetVista/ThinkCentre Troubleshooting index

  • Alias ID: MIGR-4Y67VN
  • Document ID: HT080260
  • Last Updated :6/17/2014
  • (c) 2014 Lenovo