Service manual

Troubleshooting 3-91
available to help identify the source of the error. This error bit is
implemented as a copy of the Valid bit in the MEM_RD_UCE_TRAP register.
NOTE:
To determine the array in error a valid configuration tree is required. If
this is not available, the entire memory module, including its DIMMs, will be
called out. For an uncorrectable memory error a single DIMM in error can not
be determined. As a minimum a group of 4 DIMMs will be called out (ie a
Memory Array\).
No memory write errors have been identified. So the problem source is assumed
to be the memory module or its DIMMs.
Error detail: The memory has detected a ECC checkbits all-zeros or all-ones.
Refer to Example 3–50.
The brief description summarizes the problem. In this case an
uncorrectable read error on memory module 1 of QBB0\(Soft QBB0\) has
been detected. (Though not called out at this level, this error is a 660
machine check.)
The full description of the problem gives much more detail. Here we learn
that a precise diagnosis cannot be made and a single FRU cannot be called
out.
Example 3–50 continues on the next few pages.