MAP2090 Primary power supply 208 VDC overcurrent

Use this procedure when the primary power supply (PPS) reports an overcurrent in the 208 VDC power boundary.

About this task

This can be caused by a PPS failure or a short in the distribution system.
DANGER
Hazardous voltage, current, or energy levels are present inside of a component to which this label is attached. (L001)
Safety label L001

MAP2090 Section -1

Procedure

  1. Determine the location of the PPS by using the location code listed in the problem FRU list.
  2. Observe the LED on the PPS sequencer module labeled S0 Callout label 2. Callout label 1 shows the disable/enable switch.
    Figure 1. PPS sequencer module and LED enable/disable switch
    Sequencing module in PPS, as well as the LED and enable/disable switch
    Find the condition that applies:
    • LED is amber, go to the next step.
    • LED is green, the failure is not occurring now so you will not be able to isolate the problem with this MAP. Exit this MAP and close the problem.
  3. The LED is amber. Disconnect the cable Callout label 1 from the PPS sequencer module to the 208 VDC bus bar. Reset the S0 output by setting the enable/disable switch below the LED to disable (down) and then enable (up).
    Figure 2. Disconnecting the cable from the PPS sequencer module to the 208VDC bus bar
    1. Observe the LED on the PPS sequencer module labeled S0. Find the condition that applies:
    • LED is amber, the PPS is failing. Return to the repair screen to continue the repair and replace the PPS.
    • LED is green, the failure is external to the PPS. Go to the next step.
  4. There is an overcurrent in the bus bar distribution system.
    Note: The power supplies connected to the output connectors of the secondary 208 VDC bus bar are protected by individual fuses as shown in Figure 3. Those fuses would blow before the PPS would detect an overcurrent.
    The possible failing FRUs are:
    • PPS to primary 208 VDC bus bar cable Callout label 2
    • Primary 208 VDC bus bar Callout label 3
    • Primary 208 VDC bus bar to secondary 208 VDC bus bar cable Callout label 4
    • Secondary 208 VDC bus bar Callout label 5
    Figure 3. Power supplies connected to output connectors of the 208VDC bus bar
    enter alt text here
  5. Disconnect cable Callout label 4 from connector C. Reset the S0 output by setting the enable/disable switch below the LED to disable (down) and then enable (up).
    1. Observe the LED on the PPS sequencer module labeled S0. Find the condition that applies:
    • LED is amber, the failing FRU is cable Callout label 2 or bus barCallout label 3. Go to the next step.
    • LED is green, the failing FRU is cable Callout label 4 or bus bar Callout label 5. Go to step 7.
  6. Disconnect cable Callout label 2 at connector B. Reset the S0 output by setting the enable/disable switch below the LED to disable (down) and then enable (up). Observe the LED on the PPS sequencer module labeled S0. Find the condition that applies:
    • LED is amber, the failing FRU is cable Callout label 2 or bus barCallout label 3. Go to the step 8.
    • LED is green, the failing FRU is bus bar Callout label 3. Go to step 8.
  7. Connect cable Callout label 4 to connector C.
    1. Disconnect cable Callout label 4 from connector D. Reset the S0 output by setting the enable/disable switch below the LED to disable (down) and then enable (up). Observe the LED on the PPS sequencer module labeled S0. Find the condition that applies:
    • LED is amber, the failing FRU is cable Callout label 4. Go to the step 8.
    • LED is green, the failing FRU is bus bar Callout label 5. Go to step 8.
  8. Select the FRU to be replaced:
    FRU to replace Action
    PPS to primary 208 VDC bus bar cable Callout label 2 Go to Cables to replace the FRU and then go to the next step.
    Primary 208 VDC bus bar cable Callout label 3 Go Cables to replace the FRU then return to the next step.
    Primary 208 VDC bus bar to secondary 208 VDC bus bar cable Callout label 4 Replace the FRU and then go to the next step.
    Secondary 208 VDC bus bar Callout label 5 Go to Exchange the bus bar, 208VDC secondary to replace the FRU and then return to the next step.
  9. Return to the service screen that sent you here and continue the repair by selecting the PPS in the FRU list. Do a pseudo repair of the PPS.
    Note: A pseudo repair means that you use the normal PPS FRU replace procedures, but do not disconnect cables, or physically remove the FRU as guided. The pseudo repair ensures the error conditions are properly reset and all verification tests, including FRU power on self test, are correctly run.