subscribe iconSubscribe to this information
POWER7 information

Cannot power on system unit

Perform this procedure until you correct the problem and you can power on the system.

For important safety information before continuing with this procedure, see Power isolation procedures.
  1. Attempt to power on the system. See Powering on and powering off the system for information about powering on or off your system. Does the system power on, and is the system power status indicator light on continuously?
    Note: The system power status indicator flashes at the slower rate (one flash per two seconds) while powered off, and at the faster rate (one flash per second) during a normal power-on sequence.
    • No: Continue with the next step.
    • Yes: Go to step 20.
  2. Are there any characters displayed on the control panel (a scrolling dot may be visible as a character)?
    • No: Continue with the next step.
    • Yes: Go to step 5.
  3. Are the mainline ac power cables from the power supply, power distribution unit, or external uninterruptible power supply (UPS) to the customer's ac power outlet connected and seated correctly at both ends?
    • Yes: Continue with the next step.
    • No: Connect the mainline ac power cables correctly at both ends and go to step 1.
  4. Perform the following steps:
    1. Verify that the UPS is powered on (if it is installed). If the UPS will not power on, follow the service procedures for the UPS to ensure proper line voltage and UPS operation.
    2. Disconnect the mainline ac power cable or ac power jumper cable from the system's ac power connector at the system.
    3. Use a multimeter to measure the ac voltage at the system end of the mainline ac power cable or ac power jumper cable.
      Note: Some system models have more than one mainline ac power cable or ac power jumper cable. For these models, disconnect all the mainline ac power cables or ac power jumper cables and measure the ac voltage at each cable before continuing with the next step.

      Is the ac voltage from 200 V ac to 240 V ac, or from 100 V ac to 127 V ac?

      • No: Go to step 15.
      • Yes: Continue with the next step.
  5. Perform the following steps:
    1. Disconnect the mainline ac power cables from the power outlet.
    2. Exchange the system unit control panel (Un-D1). See System FRU locations.
    3. Reconnect the mainline ac power cables to the power outlet.
    4. Attempt to power on the system.

    Does the system power on?

    • No: Continue with the next step.
    • Yes: The system unit control panel was the failing item. This ends the procedure.
  6. Perform the following steps:
    1. Disconnect the mainline ac power cables from the power outlet.
    2. Exchange the power supply or supplies (Un-E1, Un-E2). See System FRU locations .
    3. Reconnect the mainline ac power cables to the power outlet.
    4. Attempt to power on the system. See Powering on and powering off the system.

    Does the system power on?

    • No: Continue with the next step.
    • Yes: The power supply was the failing item. This ends the procedure.
  7. Is the system an 8248-L4T, 8408-E8D, or 9109-RMD?
    No:
    Go to step 9.
    Yes:
    Continue with the next step.
  8. Perform the following steps:
    1. Disconnect the mainline ac power cables.
    2. Replace the service processor card at location Un-P1-C1.
    3. Reconnect the mainline ac power cables to the power outlet.
    4. Attempt to power on the system. Does the system power on?
      No:
      Continue with the next step.
      Yes:
      The service processor card was the failing item. This ends the procedure.
  9. Is the system a 8412-EAD, 9117-MMB, 9117-MMC, 9117-MMD, 9179-MHB, 9179-MHC, or 9179-MHD?
    No:
    Go to step 14.
    Yes:
    Continue with the next step.
  10. Perform the following steps:
    1. Disconnect the mainline ac power cables.
    2. Replace the service processor card in the primary processor enclosure.
    3. Reconnect the mainline ac power cables to the power outlet.
    4. Attempt to power on the system. Does the system power on?
      No:
      Continue with the next step.
      Yes:
      The service processor card was the failing item. This ends the procedure.
  11. Perform the following steps:
    1. Disconnect the mainline ac power cables.
    2. Replace the service processor card in the first secondary processor enclosure.
    3. Reconnect the mainline ac power cables to the power outlet.
    4. Attempt to power on the system. Does the system power on?
      No:
      Continue with the next step.
      Yes:
      The service processor card was the failing item. This ends the procedure.
  12. Perform the following steps:
    1. Disconnect the mainline ac power cables.
    2. Replace the midplane in the primary processor enclosure.
    3. Reconnect the mainline ac power cables to the power outlet.
    4. Attempt to power on the system. Does the system power on?
      No:
      Continue with the next step.
      Yes:
      The midplane was the failing item. This ends the procedure.
  13. Perform the following steps:
    1. Disconnect the mainline ac power cables.
    2. Replace the midplane in the first secondary processor enclosure.
    3. Reconnect the mainline ac power cables to the power outlet.
    4. Attempt to power on the system. Does the system power on?
      No:
      Contact your next level of support.
      Yes:
      The midplane was the failing item. This ends the procedure.
  14. Perform the following steps:
    1. Disconnect the mainline ac power cables.
    2. Replace the system backplane (Un-P1). See System FRU locations.
    3. Reconnect the mainline ac power cables to the power outlet.
    4. Attempt to power on the system.

    Does the system power on?

    • No: Continue with the next step.
    • Yes: The system backplane was the failing item. This ends the procedure.
  15. Are you working with a system unit with a power distribution unit with tripped breakers?
    • No: Continue with the next step.
    • Yes: Perform the following steps:
      1. Reset the tripped power distribution breaker.
      2. Verify that the removable ac power cable is not the problem. Replace the cord if it is defective.
      3. If the breaker continues to trip, install a new power supply in each location until the defective one is found. This ends the procedure.
  16. Does the system have an external UPS installed?
    • Yes: Continue with the next step.
    • No: Go to step 18.
  17. Use a multimeter to measure the ac voltage at the external UPS outlets. Is the ac voltage from 200 V ac to 240 V or from 100 V ac to 127 V ac?
    • No: The UPS needs service. For 9910 type UPS, call IBM® Service Support. For all other UPS types, have the customer call the UPS provider. In the meantime, go to step 19 to bypass the UPS.
    • Yes: Replace the ac power cable. See System parts for FRU part number. This ends the procedure.
  18. Perform the following steps:
    1. Disconnect the mainline ac power cable from the customer's ac power outlet.
    2. Use a multimeter to measure the ac voltage at the customer's ac power outlet.
      Note: Some system models have more than one mainline ac power cable. For these models, disconnect all the mainline ac power cables and measure the ac voltage at all ac power outlets before continuing with this step.

      Is the ac voltage from 200 V ac to 240 V ac or from 100 V ac to 127 V ac?

      • Yes: Exchange the mainline ac power cable. See System parts for the FRU part number. Then go to step 1.
      • No: Inform the customer that the ac voltage at the power outlet is not correct. When the ac voltage at the power outlet is correct, reconnect the mainline ac power cables to the power outlet. This ends the procedure.
  19. Perform the following steps to bypass the UPS unit:
    1. Power off your system and the UPS unit.
    2. Remove the signal cable used between the UPS and the system.
    3. Remove any power jumper cords used between the UPS and the attached devices.
    4. Remove the country or region-specific power cord used from the UPS to the wall outlet.
    5. Use the correct power cord (the original country or region-specific power cord that was provided with your system) and connect it to the power inlet on the system. Plug the other end of this cord into a compatible wall outlet.
    6. Attempt to power on the system.

    Does the power-on standby sequence complete successfully?

  20. Display the selected IPL mode on the system unit control panel. Is the selected mode the same mode that the customer was using when the power-on failure occurred?
    • No: Go to step 22.
    • Yes: Continue with the next step.
  21. Is a function 11 reference code displayed on the system unit control panel?
  22. Perform the following steps:
    1. Power off the system. See Powering on and powering off the system for information about powering on and off your system.
    2. Select the mode on the system unit control panel that the customer was using when the power-on failure occurred.
    3. Attempt to power on the system.

    Does the system power on?

    • Yes: Continue with the next step.
    • No: Exchange the system unit control panel (Un-D1). See System FRU locations . This ends the procedure.
  23. Continue the IPL. Does the IPL complete successfully?
    • Yes: This ends the procedure.
    • No: Return to Start of Call. This ends the procedure.
Parent topic: Power problems

Send feedback Rate this page

Last updated: Tue, February 11, 2014