PWR1906

1. Power off the unit you are working on.
2. Disconnect all the I/O devices (tape, diskette, optical, and disk units) from the unit that you are working on by sliding them partially out of the unit. See the service guide for the unit you are servicing.
3. Remove and label all of the cards that are installed in the PCI adapter slots.
4. Power on the unit you are working on.

Does a power reference code occur?

• Yes: Continue with the next step.
• No: Go to step 9.

1. Power off the unit you are working on.
2. Remove, in order, all power supplies except the first one (either P00 or P01 depending on the configuration).
3. Power on the unit you are working on.

Does a power reference code occur?

• Yes: Continue with the next step.
• No: Go to step 4.

1. Power off the unit you are working on.
2. Remove the power supply that was left installed in step 2.
3. Reconnect the next power supply in order (P01 or P02).
4. Power on the unit you are working on.

Does a power reference code occur?

• Yes: Go to step 5.
• No: Exchange the power supply you removed in step 3.b.

  This ends the procedure.

1. Power off the unit you are working on.
2. Reconnect the next power supply in order.
3. Power on the unit you are working on.

Does a power reference code occur?

• No: Repeat this step until all power supplies have been reconnected.

  This ends the procedure.

• Yes: Exchange the power supply that you reconnected in this step.

  This ends the procedure.

1. Remove one of the fans from the unit you are working on that you did not previously remove during this procedure.
   Note: Disregard a fan reference code if it occurs during this step.
2. Power on the unit you are working on.

Does a power reference code occur?

• Yes: Continue with the next step.
• No: The fan that you removed in this step is the failing item.

  This ends the procedure.

• Yes: Install all of the fans and continue with the next step.
• No: Perform the following:
  1. Power off the unit you are working on.
  2. Reinstall the fan that was removed in step 5 to its original location.
  3. Repeat step 5.

1. Remove the power cable (that was not previously removed) from one of the lower DASD device boards (CB1 or CB2).
2. Power on the unit you are working on.

Does a power reference code occur?

• Yes: Continue with the next step.
• No: Replace the DASD device board that the power cable was removed from in this step.

  This ends the procedure.

• Yes: Repeat step 7.
• No: Replace the following one at a time:
  1. DASD upper device board (DB3)
  2. I/O enclosure backplane (CB1).

  This ends the procedure.

1. Power off the unit you are working on.
2. Reinstall all of the cards that you removed in step 1.
3. Reconnect the ac power cable to the unit that you are working on.
4. Power on the unit you are working on.

Does a power reference code occur?

• Yes: Continue with the next step.
• No: Go to step 12.

1. Power off the unit you are working on.
2. Disconnect one of the cards that you connected in step 9.
3. Power on the unit you are working on.

Does a power reference code occur?

• Yes: Continue with the next step.
• No: Exchange the last card that you disconnected in this step.

  This ends the procedure.

• Yes: Continue with the next step.
• No: Repeat step 10.

1. Power off the unit you are working on.
2. Reconnect all of the I/O devices (tape, diskette, optical, or disk units) that you disconnected in step 1.
3. Power on the unit you are working on.

Does a power reference code occur?

• Yes: Continue with the next step.
• No: This ends the procedure.

1. Power off the unit you are working on.
2. If you have not already done so, disconnect all of the I/O devices (tape, diskette, optical, or disk units) that you reconnected in step 12.
3. Reconnect one of the I/O devices (tape, diskette, optical, or disk units) that you just disconnected.
4. Power on the unit you are working on.

Does a power reference code occur?

• No: Continue with the next step.
• Yes: Exchange the last I/O device that you reconnected in this step.

  This ends the procedure.

• Yes: This ends the procedure.
• No: Repeat step 13 (you can skip part b).