IBM RS/6000 SP, Maintenance Information

Page: 293 / 388

MAP 0460: Scalable Electrical Power Base Unit
040 (continued)
– Check processor nodes for any Power (green) LEDs On or flashing. If no Power (green) LEDs are lit,
make sure that the circuit breaker at the front of at least one processor node or switch assembly is in
the On (‘1’) position.
Are green LEDs On or Flashing on any processor node(s) or switch assembly (excluding those due
to self-test)?
Yes No
041
No 48 V dc power at processor nodes.
– Check cable PDU-BH-P6 for an obvious problem.
Does the cable appear to be okay?
Yes No
042
– Fix the obvious cable problem.
– Go to “MAP 0570: End of Call” on page 1-357.
043
– Disconnect cable PDU-BH-P6 from SEPBU.
– With main power switch in On (‘1’) position, check for continuity between PDU-BH-P6 pin 2 and
pin 5, then check for continuity between pin 3 and pin 4.
Is there continuity in both cases?
Yes No
044
Problem with the main power switch.
– Open the main power switch assembly.
– Disconnect the white connector of the main power switch from the main power switch cable
PDU-SW-P1.
– With main power switch in On (‘1’) position, check for continuity between the two pins of the
white main power switch connector.
Is there continuity between these two pins?
Yes No
045
– Refer to "Replacing the Main Power Switch or LED" in
IBM RS/6000 SP: Mainte-
nance Information, Volume 3, Locations and Service Procedures to replace the main
power switch.
– Reconnect ac power and power on system.
– Go to Step 036 on page 1-272 to verify fix.
046
– Replace main power switch cable PDU-BH-P6.
– Go to Step 036 on page 1-272 to verify fix.
047
– Refer to "Replacing the SEPBU Power Control Interface (PCI) Card" in IBM RS/6000 SP: Mainte-
nance Information, Volume 3, Locations and Service Procedures to replace the SEPBU power
chassis.
Chapter 1. Maintenance Analysis Procedures (MAPs)
1-273