DS8000 Service Documentation Version 7.5

Exchange the UEPO switch and cable assembly

Before you begin

Icon for electrostatic discharge wrist strapUse approved ESD procedures to prevent damage.

Attention:
  • This is not a stand-alone procedure. Customer disruption and damage to the hardware might occur if microcode and power boundaries are not in the proper conditions for this service action.
  • If you were sent here by a serviceable event FRU repair, the microcode and power boundaries have already been set.
  • If you were not sent here by a serviceable event FRU repair, see MAP1230 Replace a FRU without using a serviceable event.
Notes:
  • All the cables and FRUs to be removed must be uniquely identified so they can be reinstalled correctly.
  • If an installed earthquake resistance kit prevents you from accessing this FRU, refer to MAP1600.

Remove the UEPO switch and cable assembly

About this task

The UEPO switch and cable assembly is:

  • The red UEPO switch is at the front of the rack above the Battery service module (BSM) sets.
  • The UEPO cable is permanently attached to the rear of the UEPO switch.
  • The UEPO switch and cable are two separate circuits. The switch is a double pole - single throw switch. There is one set of contacts and dedicated wires for each DC-UPS UPS.
  • The DC-UPS sends a low voltage DC signal to the UEPO switch. That signal must be returned to the DC-UPS DSU to allow it to power on. If the UEPO signal loop is open (UEPO switch tripped or a cable problem), the DC-UPS DSU will not power on at all. All LEDs will be off.
  • Each rack has its own UEPO switch.

Procedure

  1. Open the left rear cover. Remove the two screws Callout label 1 that secure the right rear cover (trained service personnel access area only).
    Open the right rear cover. (Figure 1)
    Note: The screws must be reinstalled when the cover is closed to prevent customer access.
    Figure 1. Removing retaining screws on right rear machine cover
    enter alt text here
  2. Unfasten Callout label 1 and then rotate all six power distribution units (PDUs) away from the rear of the rack.
    Figure 2. Power distribution units in normal position (rack rear view)
    Power distribution units in normal position (rack rear view)
  3. Use two PDU service tools to hold the PDUs in the open position. (Figure 3 and Figure 4).
    1. The PDU service brackets are stored in the Rack-1 front upper left documents enclosure.
    2. The upper three PDUs swing out as a group because they are held together by a removable PDU alignment bracket.
      The lower three PDUs are similar.
    3. The PDU service tool should be installed on the middle PDU of each group of three.
    4. The PDU service tool bottom tab Callout label 3 is inserted between the upper and lower PDUs.
    5. The PDU service tool fingers Callout label 1 and Callout label 2 straddle the PDU support bracket.
    6. Figure 4 shows the tool properly installed. The tool is delicate, do not put unnecessary force on the PDU group.
    Figure 3. PDU service tool
    PDU service tool
    Figure 4. PDU service tool installed
    PDU service tool installed
  4. At the rear of the rack, set the CB1 MAIN LINE SWITCH (Figure 5) to Off (down) for the upper and lower DC-UPS DSUs.
    Figure 5. Location codes for the DC-UPS (Models 961, 96E) (rear)
    Location codes for the DC-UPS (Models 961, 96E) (rear)
  5. Disconnect the UEPO switch and cable at the DC-UPS Ex-J5 connector for the upper and lower DC-UPS DSU. See Figure 5.
  6. At the front of the rack remove the UEPO switch Callout label 1 and cable assembly. See Figure 6.
    1. Remove the four screws securing the UEPO switch.
    2. Remove the cable retention hardware as needed and then remove the UEPO switch and cable assembly from the rack.
    Figure 6. UEPO switch
    UEPO switch

Install the UEPO switch and cable assembly

Procedure

  1. Route the cable assembly.
  2. Fasten the UEPO switch to the rack.
  3. Connect the cable to the Ex-J5 connector on the upper and lower DC-UPS DSU.
  4. Install the cable retention hardware.
  5. Set the CB1 MAIN LINE SWITCH (Figure 5) to On (up) for the upper and lower DC-UPS DSUs.
  6. Do both the upper and lower DC-UPS DSUs have the LOCAL AC LED Callout label 5 (Figure 7) indicators lit?
    • Yes, continue at the next step.
    • No, ensure the cable is properly connected to the DC-UPS DSU. Ensure the UEPO switch is in the normal position. If needed, use an ohm meter to check for less than one ohm resistance between the UEPO cable pins when disconnected from the Ex-J5 connector.
    Figure 7. LEDs on the DC-UPS DC Supply Unit (DSU), rear of rack
    LEDs on the DC-UPS DC Supply Unit (DSU), rear of rack
  7. Remove the upper and lower PDU service tools and return them to the document enclosure (front upper left of Rack-1).
  8. Rotate and fasten the PDUs to the closed position.
  9. Close the right rear cover and reinstall the two security screws that prevent customer access. Then close the left rear cover.
  10. Exit this service information center parts exchange procedure and return to the procedure that sent you here.