PWR1902

Refer to Power isolation procedures for important safety information before servicing the system.

Instructions for Model HV4

1. Perform the following steps:
   1. Disconnect the AC power cables or cables from the unit on which you are working.
   2. Disconnect all the I/O devices (tape, diskette, optical, and disk units) by sliding them partially out of the system unit (see Removing and Replacing FRUs).
   3. Remove and label all cards (for example, PCI adapters, memory DIMMs, GX adapter(s), RIO/HSL, and RAID cards if installed).
   4. If the SRC is 1xxx-1B01, also remove the regulators (see Physical Locations).
   5. reconnect the AC power cable or cables to the unit on which you are working.
   6. Power on the system (see Powering on and powering off).

   Does a power reference code occur?

   • Yes: Continue with the next step.
   • No: Go to step 6.
2. Perform the following:
   1. Remove one of the fans from the system unit (if you have previously removed and reinstalled any fans using this procedure, remove one of the fans that has not been removed).
      Note:
      Disregard a fan reference code if it occurs during this step.
   2. Power on the system (see Powering on and powering off).

   Does a power reference code occur?

   • Yes: Continue with the next step.
   • No: The fan you removed in this step is the failing item. Replace the failing fan, go to Removing and Replacing FRUs. This ends the procedure.
3. Have you tried removing each fan one at a time?
   • Yes: Reinstall all the fans and continue with the next step.
   • No: Perform the following:
     1. Power off the system.
     2. Install the fan that you removed in step 2 to its original location.
     3. Repeat step 2
4. Perform the following:
   1. Power off the system.
   2. Disconnect the power cable from and then remove one of the power supplies (that you have not already tried removing) from the system unit and replace it with a new one (see DUMMY PAGE FOR Part information).
   3. Power on the system.

   Does a power reference code occur?

   • No: The power supply you just removed is the failing item. Power off the system and reinstall the parts you removed in previous steps. Go to Verifying a repair. This ends the procedure.
   • Yes: Continue with the next step.
5. Remove the new power supply that you just installed in step 4 and reinstall the original power supply. Have you now tried exchanging all of the power supplies in the system?
   • No: Repeat step 4.
   • Yes: Replace the system backplane (see Physical Locations). Then reinstall the parts you removed in step 1. Go to Verifying a repair. This ends the procedure.
6. Perform the following steps:
   1. If you removed regulators in step 1, reinstall the regulators. If not, go to step 9
   2. Power on the system.

   Does a power reference code occur?

   • Yes: Continue with the next step.
   • No: Go to step 9
7. Perform the following:
   1. Power off the system.
   2. Disconnect one of the regulators you reinstalled in step 6.
   3. Power on the system.

   Does a power reference code occur?

   • Yes: Continue with the next step.
   • No: Replace the last regulator you disconnected in this step. This ends the procedure.
8. Have you disconnected all the regulators?
   • Yes: Repeat step 7.
   • No: Reinstall all the parts removed in this procedure and go to Starting a Service Call. This ends the procedure.
9. Perform the following:
   1. Reinstall all the cards (PCI adapters, memory DIMMs, GX adapter(s), RIO/HSL and RAID cards) you removed in step 1.
   2. Power on the system.

   Does a power reference code occur?

   • Yes: Continue with the next step.
   • No: Go to step 12.
10. Perform the following:
    1. Power off the system.
    2. Disconnect one of the cards you reinstalled in step 9.
    3. Power on the system.

    Does a power reference code occur?

    • Yes: Continue with the next step.
    • No: Replace the last card you disconnected in this step. This ends the procedure.
11. Have you disconnected all the cards?
    • No: Repeat step 10.
    • Yes: Reinstall all of the parts removed in this procedure and return to Starting a Service Call). This ends the procedure.
12. Perform the following:
    1. Power off the system.
    2. Reconnect all of the I/O devices (tape, diskette, optical, and disk units) that you disconnected in step 1.
    3. Power on the system.

    Does a power reference code occur?

    • Yes: Continue with the next step.
    • No: The system is working. The problem seems to be intermittent (see MAP 0040: Intermittent Problem Isolation). This ends the procedure.
13. Perform the following:
    1. Power off the system.
    2. Disconnect one of the I/O devices (tape, diskette, optical, and disk units) that you reconnected in step 12.
    3. Power on the system.

    Does a power reference code occur?

    • Yes: Continue with the next step.
    • No: Replace the last I/O device you disconnected in this step (see Locating FRUs). This ends the procedure.
14. Have you disconnected all of the I/O devices?
    • No: Repeat step 13.
    • Yes: Reinstall all of the parts you removed in this procedure and return to Starting a Service Call. This ends the procedure.