IBM RS/6000 SP, Service Manual

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5. Set the switch clock selections on the “problem” switches (refer to “Selecting appropriate switch clocks”
on page 3-6).
6. Run advanced diagnostics on “css0” on the “test” processor node and its associated switch port.
v
Do not perform cable wrap test.
v
Refer to
″
Running diagnostics in a processor node
″
in RS/6000 SP: System Service Guide .
7. Look for an SRN indicating a clock problem, such as “External clock” being listed as one of the failing
components.
Note: Do not exit from diagnostics at this time, as it may be used in the following steps.
8. Do the “css0” diagnostics fail with an indication of a clock problem?
v
If yes, the clock problem is resolved. Go to “Step 0620-043” on page 1-36 to verify fix.
v
If no, go to “Step 0620-041” on page 1-35 to replace the problem switch assembly.
Step 0620-036
The “css0” diagnostics failed at “Step 0620-033” on page 1-33 and indicated a clock problem.
1. Record current clock setting for the switch (internal/external).
2. From the control workstation, select the internal clock for this switch assembly.
3. Run advanced diagnostics on “css0” on the “test” processor node and its associated switch port.
v
Do not perform cable wrap test.
v
Refer to
″
Running diagnostics in a processor node
″
in RS/6000 SP: System Service Guide .
4. Look for an SRN indicating a clock problem, such as “External clock” being listed as one of the failing
components.
5. Do the “css0” diagnostics fail with indication of a clock problem?
v
If yes, go to “Step 0620-037”.
v
If no, go to “Step 0620-037”.
Step 0620-037
You have run the “css0” diagnostics.
1. At the SP Switch, check the data cable interposer (if present) and the switch data cable corresponding
to the original external clock selection for any obvious problem such as a loose cable connection or
swapped cables.
2. Determine which connection is the other end of the switch data cable checked in the step above.
v
Refer to Appendix A in RS/6000 SP: Installation and Relocation .
3. Check the switch data cable at the other SP Switch for any obvious problem such as a loose cable
connection or swapped cables.
4. Do the switch data cables and any data cable interposers appear to be okay?
v
If yes, go to “Step 0620-038”.
v
If no:
a. Fix the obvious cable connection problem.
b. Go to “Step 0620-043” on page 1-36 to verify fix.
Step 0620-038
The switch data cables and the data cable interposers appear to be okay.
1. Swap the data cable with another one at S00-BH-J3, S00-BH-J4, or S00-BH-J5.
2. To provide a good clock, swap the switch data cable at the switch assembly with another one.
3. Reset the clock setting to that recorded in “Step 0620-036”.
4. Run advanced diagnostics on “css0” on the “test” processor node and its associated switch port.
v
Do not perform cable wrap test.
v
Refer to
″
Running diagnostics in a processor node
″
in RS/6000 SP: System Service Guide .
SP Switch function (MAP 0620)
1-34
RS/6000 SP: SP Switch Service Guide