Exchange the bus bar, 5/12V secondary lower

Before you begin

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

About this task

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:

This procedure is disruptive and requires you to power off the storage facility.
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.

Decide if you are going to remove the upper or the lower bus bars and select the condition that applies:

You are here to replace a bus bar in the lower half of an expansion rack, go to step 1.
You are here to replace a bus bar in a base rack, go to Exchange the bus bar, 5/12V secondary upper.
You are here to replace a bus bar in the lower half of an expansion rack, go to Exchange the bus bar, 5/12V secondary upper.

Remove the bus bar, 5/12V secondary lower

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.
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). See Figure 1.
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? See Figure 2.

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 9.
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 on a PC platform. In the navigation area, select the Removing and Replacing Parts Rack power and cooling section and select this FRU procedure. 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.
Open the 208 VDC bus bar gate to service position. See Figure 3.
1. Remove the two screws and open the 208 VDC bus bar gate to the service position.
  
  Figure 3. 208VDC bus bar gate service position
Have the customer remove power from the storage facility (see Figure 4):
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 PPS the customer has removed power from.
    2. Have the customer restore power to the PPS. 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 the PPS is powered back 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 the PPSs.
1. At both PPSs, set the PPS ac input power module CB00 switch to Off (down).
2. At both PPSs, disconnect the mainline power cord from the PPS ac input power module. Push the two release levers .
  Figure 4. Power supply main line CB00 switch
3. Remove the cable ties securing the mainline power cable to PPS-2 (lower PPS). See Figure 5.
4. Remove the screw and mainline power cable bracket . See Figure 5.
  Figure 5. Power supply main line
Disconnect the rear cables:
1. At the rear of both PPS-2 (lower), disconnect all the cables.
2. Remove the cable ties.
3. Remove the green/yellow ground wire from both the PPSs. Keep the serrated washers.
Put PPS-2 (lower) in service position 2.
1. At the front of the rack, remove the eight black hex head screws that fasten the PPS-1 chassis to the rack. See Figure 6.
  Figure 6. PPS chassis remove
2. Slide PPS-2 out to service position 2. 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. See Figure 7.
  Figure 7. PPS service 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.
At the front of the rack, remove the two screws securing the PPS to the sheet metal tray . See Figure 8.
Figure 8. PPS sheet metal screws
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.) See Figure 9.
Figure 9. Sliding PPS out on sheet metal tray
Remove the primary to secondary tie bars. See Figure 10.
1. At the rear of the rack, remove the lower primary to secondary tie bar plastic cover. Loosen but do not remove the two screws .
2. The plastic cover has keyhole slots. The cover has tabs that slide behind the lower and low tie bar. Slide the cover up , and then remove it.
  Figure 10. Bus bar cover
3. Remove the bolt securing each end of each lower tie bar and remove the tie bars . See Figure 11.
  Figure 11. Lower tie bars
Remove two storage enclosures (if installed).
1. At the rear of the rack, remove the middle two storage enclosures (if installed) in the lower half of the rack. See Figure 12.
  Figure 12. Middle storage enclosures
2. Each storage enclosure, disk drive module (DDM) , fiber channel interface card and FC-AL cable must be in the exact same position when reinstalled in later steps. See Figure 13
3. Observe the cable labeling to ensure you will be able to replug the cables correctly. Disconnect the FC-AL cables from the two fiber channel interface cards (FCIC) . Squeeze the top of the FC-AL cable connector to release it from the FCIC card.
  Note: There are four FC-AL cables if this is the last storage enclosure in this group. There are eight FC-AL cables if this is not the last storage enclosure in this group.
4. Remove the four screws fastening the storage enclosure to the rack mount rails.
  Figure 13. DDM Fibre Channel cable
5. Remove each DDM and FCIC card from the storage enclosure and set them in a safe place. You must ensure each one will be plugged in the same position in the new storage enclosure. It is recommended that you write down the serial number and position of each part before you remove them.
Remove the 5/12V secondary bus bar. See Figure 14.
1. Disconnect the four storage enclosure power cables from the secondary bus bar. Squeeze the top and bottom release levers on the cable connector and then pull to release. The front storage enclosure cables connect to the front 5/12V secondary bus bar A. The rear storage enclosure cables connect to the front 5/12V secondary bus bar B.
2. Remove the nuts and washers fastening the bus bar to the rack and then remove the bus bar.
  Figure 14. Storage enclosure cables to bus bar

Install the bus bar, 5/12V secondary lower

Procedure

Install the bus bar and connect the cables.
1. Install the 5/12V secondary bus bar on the mounting studs. Install the washers and nuts.
2. Install the primary to secondary tie bars.
  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.
3. Install the tie bar plastic cover.
  - There are tabs on the inside of the cover that must slide down behind the tie bars.
  - The keyhole slots in the cover must slide over the two screws near the PPS.
  - Tighten the two screws.
4. Connect the four storage enclosure power cables to the bus bar.
Install any storage enclosures that were removed:
1. Install the storage enclosure in the original position in the rack and fasten it with the four screws.
2. Install each disk drive module (DDM) and Fibre Channel interface card in the exact same position as it was in the old storage enclosure.
3. Install each FC-AL cable in the exact same position as it was in the old storage enclosure.
Place PPS-2 in the normal position:
1. At the front of the rack, push PPS-1 fully in on the sheet metal tray and install the two screws . See Figure 8.
Put the PPS 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 6.
At PPS-1 connect the rear cables:
1. At the rear of PPS-1, connect all the cables.
2. Install the cable ties.
3. Install the green/yellow ground wire. 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. Set the PPS ac input power module CB00 switch to On (up).
3. Instruct the customer to switch on the mainline circuit breaker that supplies mainline ac voltage to the power receptacle for PPS-1.
4. At the front of the rack, observe the PPS AC INPUT GOOD LED. Is the LED off on both PPSs?
  - Yes, go to the next step.
  - No, return to step 6.
208 VDC bus bar gate to normal position:
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.