Exchange the PPS (primary power supply)

Before you begin

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

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.

DANGER

Hazardous voltage, current, or energy levels are present inside of a component to which this label is attached. (L001)

Remove the primary power supply (PPS)

About this task

The base primary power supply (PPS) FRU is made up of five modules. Two modules are at the front of the rack, and three modules are at the rear. The PPS chassis is sheet metal only and is never replaced unless it is damaged. Additional optional modules may be present in the rear, but those are not replaced.

Note: It is normal for various PPS LED indicators to stay lit until the mainline input CB is switched off and the J3 PPS-to-PPS communication cable is disconnected. The communication cable supplies signals and logic voltages so the PPS control circuitry can stay active in the event of loss of input power to one PPS.

Procedure

Two CEs are needed for step 1d.
1. The PPS FRU only requires the five base PPS modules be replaced as stated later in this procedure.
2. The PPS sheet metal enclosure and front fan assembly will not be replaced.
3. IBM ships an entire pretested PPS on a pallet which ensures all 5 base modules are working.
4. To remove and replace the modules in the FRU PPS on the pallet, one end of the PPS enclosure at a time will need to be temporarily lifted and set upon the packing materials as shown.
  
  CAUTION:
  Lifting one end of the PPS exceeds the single CE weight limit, so two CEs are required.
Figure 1. PPS FRU packaging (Model 941 PPS is shown; Model 951 PPS is similar)
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.
Do not use the PPS FAULT LED indicator to identify the PPS being repaired.
- When the failing PPS is being repaired, the PPS FAULT LED indicator on the working PPS in the same rack might be on solid.
  The working PPS is indicating that the PPS being repaired is not available for use.
- Use the FRU Identify LED indicator to identify the PPS being repaired.
Figure 2. LEDs on the PPS (front)
Have the customer remove power to the PPS being replaced.
1. Instruct the customer to switch off the circuit breaker that supplies mainline ac voltage to the power receptacle for the primary power supply (PPS) you are repairing.
  Attention: Use lockout and tagout procedures as defined in the Electrical Safety for IBM® Customer Engineers.
2. Observe the front of the PPS. Is the AC INPUT GOOD LED indicator off?
  - Yes, the customer has removed power from the correct PPS. Continue with the next step.
  - No, stop. The customer has not removed power from the correct PPS.
    1. Determine which PPS the customer has removed power from.
    2. Have the customer restore power to the PPS. The PPS may not power back on fully.
    3. Observe the front PPS LED indicators with a PPS that is fully powered on. If the PPS did not power on fully, you will 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 PPS.
To gain full access to the rear of the PPS, unfasten and then rotate the power distribution units (PDUs) away from the rear of the PPS.
Figure 3. Power distribution units in normal position (rack rear view)
Remove power and mainline power cord from the PPS.
1. Set the PPS ac input power module CB00 switch to Off (down) .
2. Disconnect the mainline power cord from the PPS ac input power module. Push the two release levers .
  
  Figure 4. Remove the ac mainline power cord
3. If repairing PPS2 (the lower PPS), remove the cable ties securing the mainline power cable to PPS2 (lower PPS). Remove the screw securing the mainline power cable bracket, and then remove the mainline power cable bracket . See Figure 5.
  
  Figure 5. Power supply main line
At the rear of the PPS REMAINING IN USE by the customer, disconnect the PPS-to-PPS communication cable at the bottom right of the PPS sequencer module (see Figure 6).
Notes:
1. Disconnecting the cable from the working PPS will protect the working PPS. Then, when the other end of the cable is disconnected from the PPS being repaired, no pins inside that connector will be able to touch ground and shut down the working PPS that remains in use.
2. This removes the remaining logic power from the PPS being repaired, and all PPS LEDs should now be off.
Figure 6. PPS rear view, lower right: PPS-to-PPS communication cable connection
At the rear of the PPS BEING REPAIRED, disconnect the PPS-to-PPS communication cable at the bottom right of the PPS sequencer module.
Disconnect the remaining cables from the rear of the PPS.
1. At the rear of the PPS, disconnect all the cables.
2. Remove the cable ties.
3. Remove the green/yellow ground wire from the PPS, leaving the other end attached to the rack frame ground.
4. Visually inspect the ground wire attached to the frame ground. Is it in good condition?
  - Yes, the ground wire is in good condition. Reuse it and discard the one supplied with the replacement PPS.
  - No, the ground wire is damaged or there is doubt.
    Carefully remove the ground wire at this time and replace it with the one supplied with the replacement PPS.
Unscrew the two silver thumbscrews securing each PPS rear module. Do not remove the modules at this time.
If replacing the PPS-1 (upper PPS), at the front of the rack (see Figure 7):
- Remove the two screws .
- Remove the door latch bracket .
Figure 7. Rack front door-latch bracket
Remove fans and front modules.
1. At the front of the rack, unplug the three fan cables . See Figure 8.
2. Unscrew the eight silver thumbscrews securing the PPS fan assembly . Then, lift the fan assembly up off the two bottom positioning studs and remove it from the rack. One or more of the PPS LEDs may now be lit.
  Figure 8. Remove fan cables and fan assembly screws
3. Remove the 208VDC base module and the PFC module . See Figure 9.
  - Unplug the three cables from the PFC module.
  - Unscrew the two silver thumbscrews securing the modules.
  - Use the swing up handles to remove each module.
  Figure 9. 208VDC base module and PFC module
Slide the PPS out just far enough to allow you to remove the rear modules. This step is optional if you feel you can remove the PPS rear module(s) with the PPS in the current position.
1. At the front of the rack, remove the eight hex head screws that fasten the PPS chassis to the rack . See Figure 10.
  Figure 10. Primary power supply (PPS) retaining screws
2. Slide the PPS out just far enough to allow you to remove the rear modules. Figure 11 shows the PPS fully forward.
  Figure 11. Move PPS to service position
Remove rear modules.
1. The next steps may require you to remove one or more frame cable routing brackets from the rear of the frame so that there is clearance to remove the PPS modules. Each bracket is held by two screws that only need to be loosened, not removed, for the bracket to be moved. See Figure 12, .
  Figure 12. Cable routing brackets
2. At the rear of the rack, remove the sequencer module . Move the release lever down and then slide the module out. See Figure 14.
  Note: If the sequencer module slides out about 1 inch (2.5 cm) and then stops, it is hitting the PPS tray tab beneath it. The PPS assembly will need to be moved slightly to the right. At the bottom left of the PPS, insert a screw driver between the PPS tray vertical sheetmetal and the PPS. See Figure 13, . Apply gentle pressure to move the PPS assembly to the right until the sequencer module releases.
  
  Figure 13. Gently pry PPS assembly to right
  
  Figure 14. Remove sequencer module
3. Remove the ac input power module. See Figure 15.
4. Remove the PPS 208V DDM power module in location Ex-E1. See Figure 15.
5. Do not remove the optional modules or filler plates in locations Ex-E2.
6. Remove the PPS 208V DDM power module in location Ex-E3.
Figure 15. Location codes for the PPS (rear)

Install the primary power supply (PPS)

Procedure

Do not connect any rear cables until directed in later steps. The rear cables will be connected in a specific sequence.
Note: Failure to follow the recommended sequence may result in arcing at the connectors when connecting cables to the 208V DDM power modules.
At the rear of the PPS, install both PPS 208V DDM power modules and the AC input module.
1. Install both PPS 208V DDM power modules in locations Ex-E1 and Ex-E3. See Figure 15.
2. Install the AC input power module. Fasten the silver thumbscrews securing the modules. See Figure 15.
At the rear of the PPS, install the sequencer module. See Figure 16
1. Ensure the CB00 switch is Off (down).
2. Start with the release lever in the down position as you slide the module into the PPS.
3. Move the release lever up to fully seat the module.
Figure 16. Install sequencer module
If the PPS was moved out to the service position, move it back in to the operating position.

Figure 17. Move PPS to operating position
1. At the front of the rack, press the slide release levers and then slide the PPS chassis fully into the rack. See Figure 17.
2. Install the eight hex head screws that fasten the PPS chassis to the rack . See Figure 10.
3. If you are repairing PPS2 (lower PPS) FRUs at the rear of the rack, install the mainline power cord PPS2 bracket (if present).
At the front of the rack, install the door latch bracket with two screws.
At the front of the PPS, install both front modules and fan assembly. See Figure 9.
1. Install the 208VDC base module and the PFC module . See Figure 9.
  1. Screw in the two silver thumbscrews securing the modules.
  2. Connect the three cables from the PFC module.
2. Place the PPS fan assembly on the two vertical guide pins at the bottom of the PPS and then tighten the eight silver thumbscrews .
3. Connect the three fan cables . See Figure 8.
4. If replacing PPS-1 (upper PPS):
  1. Pivot the rack operator panel in the normal position and secure it with two screws.
  2. Install the door latch bracket with two screws.
At the rear of the PPS, fasten the two silver thumbscrews securing each PPS module.
Ensure that the enable/disable switches on the rear modules are in the On position (up).
At the front of the PPS, ensure that there are no LED indicators lit or blinking.

Note: If a PPS LED is lit, one or more cables are connected that should not be connected. Disconnect them and then repeat this step.
At the rear of the PPS, connect the and cables to the sequencer module.

Figure 18. PPS rear view, lower right: PPS-to-PPS communication cable connection
At the rear of the PPS, connect the J6 cable. See Figure 18.
At the front of the PPS, observe the LED indicators.
Are any lit?
- Yes, stop and contact your next level of support. You have the "failed diode" problem in one of the battery enclosures in this rack.
  You can continue to complete the PPS replacement. After that is complete, isolate and repair the "failed diode" problem.
- No, go to the next step.
At the rear of the PPS BEING REPAIRED, connect the PPS-to-PPS communication cable at the bottom right of the PPS sequencer module. See Figure 18.
At the rear of the PPS REMAINING IN USE by the customer, connect the PPS-to-PPS communication cable at the bottom right of the PPS sequencer module. See Figure 18.
Note: One or more of the PPS LEDs may now be lit on the PPS being repaired.
Connect the remaining rear cables except for these (see Figure 19):
1. Do not connect the mainline power cord to the PPS AC input module until directed to.
2. Do not connect the 208V power cables to the PPS modules, including:
  - Power cable to 208V DDM power modules Ex-E1 and Ex-E3 connector J1-C (see Figure 15)
  - Power cable to 208V booster power module Ex-E2 (if present) (see Figure 15)
  - Power cable to PPS sequencer module Ex-S1 connector J8-1 (see Figure 15)
The 208V power cables are connected in a separate procedure after the PPS has powered on and been tested. Do not connect them until directed to.

Figure 19. PPS 208V DC cables
Install the green/yellow ground wire, ensuring all the contact washers are in place.
Order of installation:
1. Star washer (closest to chassis)
2. Ground lug
3. Plain washer
4. Split washer
5. Nut
Ensure the PPS AC input power module CB00 switch is Off (down)
Connect power.
1. Connect the mainline power cable to the PPS and ensure 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.
Set the PPS AC input power module CB00 switch to On (up).
Instruct the customer to switch on the mainline circuit breaker that supplies mainline AC voltage to the power receptacle for the primary power supply you are repairing.
Rotate and fasten the PDUs to the closed position.
Exit this service information center parts exchange procedure and return to the procedure that sent you here.