Exchange the bus bar, 5/12V primary

Before you begin

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

Attention:

This procedure is not a stand-alone procedure. Customer disruption and damage to the hardware might occur when microcode and power boundaries are not in the proper conditions for this service action.
If a serviceable event FRU repair directed you to this procedure, the microcode and power boundaries are already set.
If a serviceable event FRU repair did not direct you to this procedure, 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.
This procedure is disruptive and requires the storage facility to be powered off.

Remove the primary 5/12V bus bar

Procedure

To locate this FRU, take one of the following actions and then return here and continue to replace the FRU:
- If this FRU has a FRU identify indicator, use the FRU identify indicator, which is listed in MAP1240 Locating FRUs by using identify indicators. If not, use the location code.
  Note: There might be cases where the FRU failure or fencing conditions prevent the FRU LED indicator from being lit even if the FRU has power.
- Use the location code, which is listed in MAP1245 Finding FRUs by using location codes.
- If there is no FRU identify indicator or location code, you were sent here by an isolation MAP or symbolic FRU procedure. Use the information in that procedure and the figures in this procedure to locate the proper part to exchange.
Most, but not all, FRUs have identify indicators. Use the flashing amber or solid blue FRU identify indicators to ensure that you are working on the correct enclosure or FRU.
- The light path identify LEDs are a hierarchy of LEDs that can identify the rack, enclosure, FRU, and even the FRU connector to which a cable is connected.
- For more information, refer to MAP1240 Locating FRUs by using identify indicators.
Use the management console to power off the storage facility subsystem.
Set the local/remote switch card white switch to Local (down). This will prevent the rack from being unexpectedly powered up by the management console (or remote power control if the feature is installed).
Figure 1. Location of the local remote switch card and the zSeries local remote switch card
Does the rack that you are repairing contain an integrated management console?

Figure 2. Visual overview of Model 941 Rack-1, front
- Yes, go to the next step.
- No, go to the 208 VDC bus bar gate to service position instructions in step 10.
Is this management console being used to guide this repair?
- Yes, you will need to use the service information center to guide this FRU replacement. Bring up the Information Center CD in a PC platform. In the navigation area, select the Exchanging Parts Rack power and cooling section and select this FRU procedure. Then, go to the next step.
- No, go to the next step.
Shut down the management console.
1. From the navigation area, click HMC Management.
2. In the right work area, go to the Operations section and click Shut Down or Restart.
  The Shutdown or Restart window opens.
3. Select Shutdown HMC, then click OK.
4. Wait for the HMC to power off then go to the next step.
Power off the management console display.
If this is an expansion rack and it has old level sheet metal, the sheet metal baffle to the left of the gate and at the bottom of the storage enclosure chassis might need to be removed to allow the gate to swing open. Remove the two screws that fasten the baffle to the 19" rack mount vertical rails. If the baffle is the new level sheet metal, it has a flexible plastic cutout that bends out of the way when the gate is swung open.
Figure 3. Air baffle
Remove the two screws and open the 208 VDC bus bar gate to the service position.

Figure 4. 208VDC bus bar gate service position
At both PPSs, have the customer remove power:
1. Instruct the customer to switch off the circuit breakers that supply mainline ac voltage to both power receptacles for the main line power cables to the rack that will have the bus bar FRU replaced.
  Attention: Use lockout and tagout procedures as defined in the Electrical Safety for IBM® Customer Engineers.
2. Observe the front of both PPSs. Is the AC INPUT GOOD LED indicator off?
  - Yes, the customer has removed power from the correct PPSs. Continue at the next step.
  - No, stop. The customer has not removed power from the correct PPSs.
    1. Determine which PPSs the customer has removed power from.
    2. Have the customer restore power to the PPSs. The PPS might not power back on fully.
    3. Observe the LED indicators on the front of both PPSs with a PPS that is fully powered on. If the PPS did not power-on fully, you need to do a pseudo repair of the PPS to power it on. A pseudo repair of the PPS means that you use the normal FRU replacement procedures, but you do not replace or even disconnect the PPS cables. Refer to MAP1230 Replace a FRU without using a serviceable event.
    4. After both PPSs are powered on, return to this step and have the customer switch off the circuit breaker to the proper PPSs.
Remove power and mainline power cord from both PPSs.
1. At both PPSs, set the ac input power module CB00 switch to Off (down).
2. At both PPSs, disconnect the mainline power cord from the ac input power module. Push the two release levers .
  Figure 5. Power supply main line CB00 switch
3. Remove the cable ties securing the mainline power cable to PPS-2 (lower PPS).
4. Remove the screw and mainline power cable bracket.
At both PPSs, disconnect the rear cables:
1. At the rear of both PPSs, disconnect all the cables.
2. Remove the cable ties at both PPSs.
3. Remove the green/yellow ground wire from both the PPSs.
4. At the front of the rack:
  - Remove the two screws and swing open the rack operator panel.
    Figure 6. Rack and power operator panel UEPO open
  - Remove the two screws and remove the door latch bracket .
    Figure 7. Rack and power operator panel UEPO door latch
Put both PPSs in service position 1 (partially extended):
1. At the front of the rack, remove the eight black hex head screws that fasten each PPS chassis to the rack.
  Figure 8. PPS chassis remove
2. Slide both PPSs out to service position 1 (partially extended). The PPS rail detents will click at service position 1 and then will prevent the PPS from being pushed back in to the normal position.
  Note: To allow the PPS to be pushed back in, you must pull the PPS out to service position 2 (fully extended), release both slide detents and then push the PPS chassis in fully.
  
  Figure 9. PPS service position
Disconnect cables from bus bars:
Note: You might need to remove both bus bars to get the bus bar being replaced removed.
1. Disconnect the cables through from the top and middle connectors on both bus bars.
  Figure 10. 5/12V bus bar top and middle cable connectors
2. Remove the screw at the top of the bus bar cable cover and then remove the cover.
  Figure 11. 5/12V bus bar cable cover screw
3. Remove the 5/12V power cables from the bus bar being replaced. Remove the bolt securing each cable.
  Figure 12. 5/12V bus bar cable bolts
Remove the primary to secondary tie bars:
1. Move PPS-1 (upper PPS) to service position 2 (fully extended on rails).
2. At the front of the rack, remove the two screws securing the PPS to the sheet metal tray.
  Figure 13. PPS sheet metal screws
3. Pull the PPS out about 5 cm (2 inches) further on the sheet metal tray as shown. (This will give more clearance at the back of the PPS for the next step.)
  Figure 14. Sliding PPS out on sheet metal tray
4. At the rear of the rack, remove the primary to secondary tie bar plastic cover. Loosen but do not remove the two screws . The plastic cover has keyhole slots. The cover has tabs that slide behind the upper and low tie bar. Slide the cover up , and then remove it.
  Figure 15. Bus bar cover
5. Remove the bolt securing each end of each tie bar and remove the tie bars .
  Figure 16. Lower tie bars
Remove the primary bus bar:
1. Remove the nuts and washers securing the bus bar to the frame, and then remove one or both bus bars as needed.
  Figure 17. 5/12V bus bar frame nuts and washers

Install the primary 5/12V bus bar

Procedure

Install the 5/12V primary bus bars on the mounting studs. Install the washers and nuts.
Install the primary to secondary tie bars.
Note: The bolts must be torqued to 8 to 11 newton meters (6 - 8 foot pounds) to make proper contact. It is recommended that you use a torque wrench if one is available. DO NOT OVERTIGHTEN or the threads in the copper bus bars might strip.
Install the tie bar plastic cover.
1. There are tabs on the inside of the cover that must slide down behind the tie bars.
2. The keyhole slots in the cover must slide over the two screws near the PPS.
3. Tighten the two screws.
Install each 5/12V power cable to the bus bar by using a bolt . See Figure 12.

Note: The bolts must be torqued to 8 to 11 newton meters (6 - 8 foot pounds) to make proper contact. It is recommended that you use a torque wrench if one is available. DO NOT OVERTIGHTEN, or the threads in the copper bus bars might strip.
Install the bus bar cable cover and secure it with the screws . See Figure 15.
Connect the cables through to the top and middle connectors on both bus bars. See Figure 10.
At the front of the rack, push each PPS fully in sheet metal tray and install the two screws. See Figure 13.
Put both PPSs back to the normal position.
Note: To allow the PPS to be pushed back in, you must pull the PPS out to service position 2 (fully extended), release both slide detents and then push the PPS chassis in fully.
Install the eight black hex head screws that fasten each PPS chassis to the rack. See Figure 8.
At the front of the rack:
1. Close the rack operator panel and install the two screws . See Figure 6.
2. Install the door latch bracket with two screws . See Figure 7.
At both PPSs, connect the rear cables:
1. At the rear of both PPSs, connect all the cables.
2. Install the cable ties at both PPSs.
3. Install the green/yellow ground wire on both PPSs. Ensure that the serrated washer is between the wire and the PPS or frame.
Connect power:
1. Connect the mainline power cable to the PPS and ensure that both latches are secure.
2. Secure the mainline power cable from PPS-1 (upper PPS) to the PPS-2 mainline power cable bracket with the cable ties.
3. Set the PPS ac input power module CB00 switch to On (up).
4. Instruct the customer to switch on the mainline circuit breaker that supplies mainline ac voltage to the power receptacle for the primary power supply that you are replacing.
208 VDC bus bar gate to normal position 1:
1. Pivot the 208 VDC bus bar gate closed being careful that both mainline power cables lay in the space between the two 208 VDC bus bars. Fasten the gate shut with the two screws.
  
  Note: If this is an expansion rack and the sheet metal baffle to the left of the gate was removed, reinstall it now with the two screws.
Power on the rack:
1. Set the local/remote switch card white switch to Remote (up). See Figure 1.
2. Use the management console to power on the storage facility subsystem.
Exit this service information center parts exchange procedure and return to the procedure that sent you here.