MAP2180 UEPO switch replacement (Models 94x, 95x, 96x)

The UEPO switch can be replaced while the storage facility is operational, even when one side of the switch or the wires that connect that side to a primary power supply are defective.

MAP2180 Section-1

Procedure

Choose the UEPO switch FRU replacement method.

MAP2180 Section-2

Before you begin

Do not disconnect the UEPO switch cable connector at J4 on the back of either PPS until instructed.

About this task

This procedure will not test the ability of the new UEPO switch to actually power off the storage facility. Instead it will check that the new UEPO switch contacts do open before it is connected to the PPS.

Procedure

  1. Use a volt/ohm meter to check the continuity of the new FRU between the two pins on the cable connector that would plug to the PPS J4 connector. With the switch in the closed position, the continuity should be less than 0.1 ohm. With the switch in the open position, the continuity should be infinite. Ensure both cables connectors checkout correctly before you continue.
  2. The next steps show and describe the Model 94x. The 95x is similar.
  3. At the front of the rack, remove the two rack operator panel screws  1 . See Figure 1.
    Figure 1. Rack operator panel LED assembly
    Rack operator panel LED assembly
  4. WARNING: Open the rack operator panel gently. Do not force it!
    Note: A few racks built before September 2007 may have the cable to the UEPO switch installed without enough free play. Forcing the panel open could cause the cable to break the UEPO switch.
  5. At the rear of the operator panel, remove the four screws (two in front and two on the left side) that hold the rear sheet metal cover that blocks access to the rear of the UEPO switch.
  6. Remove the two screws fastening the UEPO switch to the operator panel and remove the UEPO switch. Temporarily leave the switch assembly hanging by its wires. Ensure it does not contact any exposed circuits. The old UEPO switch assembly and its associated cables will be removed later in the procedure.
  7. Observe the top label on the UEPO switch and ensure it is facing up. (There are two versions of the switch, one that has the wires connected to the bottom four pins, the other connecting to the top four pins. The top label ensures it is installed in the correct orientation.) Mount the new UEPO switch assembly on the front cover with the top label facing up.
  8. Mount the new UEPO switch assembly to the operator panel.
  9. Ensure the new UEPO switch setting is ON (up).
    Note: To set the UEPO switch up, some service representatives use a key to push up through the front to set the UEPO switch to on.
  10. Route but do not connect the UEPO switch assembly cables to the appropriate primary power supply.
  11. Observe the UEPO LOOP GOOD LED indicator on the front of both PPSs. Find the condition that applies:
    • LED is lit on both PPSs, go to step 12.
    • LED is off on PPS-1 (top PPS), go to step 12.
    • LED is off on PPS-2 (bottom PPS), go to step 13.
  12. Make a connection to PPS-1 by performing the following steps.
    1. Use the utilities at the management console to select System Level Deactivate for PPS-1.
    2. Switch off the PPS-1 power input circuit breaker.
    3. Unplug the UEPO cable connected to the PPS-1 connector J4.
    4. Connect the cable from the new UEPO switch assembly.
    5. Switch on the PPS-1 power input circuit breaker.
    6. Ensure the "UEPO LOOP GOOD" LED indicator is now on.
    7. Use the utilities at the management console to select System Level Activate for PPS-1.
    8. Go to step 14.
  13. Make a connection to PPS-2 by performing the following steps.
    1. Use the utilities at the management console to select System Level Deactivate for PPS-2.
    2. Switch off the PPS-2 power input circuit breaker.
    3. Unplug the UEPO cable connected to the PPS-2 connector J4.
    4. Connect the cable from the new UEPO switch assembly.
    5. Switch on the PPS-2 power input circuit breaker.
    6. Ensure the "UEPO LOOP GOOD" LED indicator is now on.
    7. Use the utilities at the management console to select System Level Activate for PPS-2.
  14. Find the condition that applies:
    • The new UEPO switch has been connected to both PPSs. Go to the next step.
    • The new UEPO switch has not yet been connected to PPS-1. Go to step 12.
    • The new UEPO switch has not yet been connected to PPS-2. Go to step 13.
  15. Remove the old UEPO switch assembly.
  16. Complete the routing for the new cables. Ensure the cable at the operator panel has enough free play before installing the cable retention hardware.

MAP2180 Section-3

Procedure

  1. Power off the storage facility.
  2. Switch off the PPS-1 and PPS-2 power input circuit breakers.
  3. Observe the "top" label on the UEPO switch and ensure it is facing up. (There are two versions of the switch, one that has the wires connected to the bottom four pins, the other connecting to the top four pins. The "top" label ensures it is installed in the correct orientation). Replace the UEPO switch assembly. Refer to Exchange the PPS to rack operator panel UEPO cable and switch assembly.
  4. Set the UEPO switch to on.
  5. Switch on the PPS-1 and PPS-2 power input circuit breakers.
  6. Observe the UEPO Loop Complete LED on PPS-1 and PPS-2. Are both LEDs lit?
    • Yes, go to step 8.
    • No, at the PPS with the LED off, unplug the UEPO switch cable from the PPS connector J4. Go to the next step.
  7. Use a volt/ohm meter to check the continuity between the two pins on the cable connector that is unplugged from the PPS J4 connector. With the switch in the closed position (UEPO not active), the continuity should be less than 0.1 ohm. Is the continuity less than 1 ohm in the closed position?
    • Yes, the UEPO switch assembly is working. The PPS has a failure of the LED or the UEPO circuit. Set the UEPO switch to the normal position and attempt to power on. If the PPS powers on, the LED is failing. If the PPS does not power on, the PPS is failing and should be replaced.
    • No, the UEPO switch is failing and needs to be replaced.
  8. Set the UEPO switch to active. Observe the UEPO Loop Complete LED on PPS-1 and PPS-2. Are both LEDs off?
    • Yes, the UEPO circuits are working properly. Go to step 9.
    • No, the UEPO switch is failing to open the UEPO loop circuit. Go to MAP2180 Section-2 to replace the UEPO switch assembly.
  9. Set the UEPO switch back to the normal operational state. Start the power to the storage facility and when it is ready, return it to customer use.