MAP 0440: Short in 48 Volts DC Power Distribution
– Remove rear panel of Power Distribution Unit dc section.
– With all power removed from the system. Disconnect busbars from 48 V power chassis dc lugs.
– Check continuity between +48 V and -48 VRtn busbars.
Is there continuity b48 V and -48 VRtn busbars?
Yes No
003
– Reconnect busbars to 48 V power chassis lugs.
– Reinstall Power Distribution Unit dc section cover.
– Unseat all bulk dc power supplies.
– Reconnect ac power and power on system.
– Put main circuit breaker in the On (‘1’) position.
– Reseat all bulk dc power supplies one at a time, flip the bulk power supply circuit breakers
to On (‘1’) position, then check that yellow and green LEDs are lit when reseated.
Do any bulk power supplies light both yellow and green LEDs?
Yes No
004
DANGER
High voltage present. Perform “Lockout/Tagout Procedure for PDU” on
page 1-2 or “Lockout/Bagout Procedure for PDU” on page 1-3 to remove
primary power to the frame.
– Replace power supply chassis.
– Reconnect ac power and power on system.
– Go to “MAP 0570: End of Call” on page 1-357.
005
– Replace any bulk dc power supplies which cause bulk dc power supply green LED(s) to go
off or cause main circuit breaker to trip to Off (‘0’) position.
– Go to “MAP 0570: End of Call” on page 1-357.
006
– Remove plastic cover over busbars.
– Check for an obvious short between the +48 V and -48 VRtn busbars.
Is there an obvious short between the +48 V and -48 VRtn busbars?
Yes No
007
Short in tailgate cables PDU-BH-J1, PDU-BH-J2, PDU-BH-J3, PDU-BH-J4, and/or
PDU-BH-J5.
– Set multimeter to constantly check continuity between the +48 V and -48 VRtn busbars.
– Starting from closest connection, start removing cable connections to the '+' busbar. Repeat
this until there is no longer continuity.
– Replace dc tailgate cable connected to the wire you just removed.
– While checking continuity, start reattaching the cable connections you had removed above.
Replace any other cables which cause continuity between the +48 V and +48 VRtn
busbars.
(Step 007 continues)
1-258
RS/6000 SP MAPs
Summary of Contents for RS/6000 SP
Page 1: ...RS 6000 SP IBM Maintenance Information Volume 2 Maintenance Analysis Procedures GA22 7376 01...
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Page 60: ...MAP 0130 Processor Node Figure 1 7 Thin Node High Level Diagram 1 40 RS 6000 SP MAPs...
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