The disk drive might be failing.

Do the following:

1. Is the device location information available in the Service Action Log?
   • No: Continue with the next step.
   • Yes: Exchange the failing item, to exchange the failing item, see the "Disk unit recovery procedure" in the service guide for the system unit. This ends the procedure.
2. Find the direct select address and the device address. See System reference code (SRC) address formats.
3. See Locating FRUs and find the diagram of the system unit or expansion unit. Use the direct select address and the device address to find the location of the disk unit.
4. Is the SRC reported on the control panel?
   • No: Continue with the next step.
   • Yes: See System reference code (SRC) address formats. The two rightmost characters of word 2 define the SRC format. Use the correct SRC format to locate the function that contains the characters tttt lmmm, where:
     • tttt = Type number
     • l = Level
     • mmm = Model

   Then go to step 6.

5. Remove the disk unit to determine the part number. Replace the disk unit. This ends the procedure.
6. Using the drive type, refer to the Managing Devices document, order number SA76-0107 for disk drive FRU part numbers. If you do not know the type, remove the disk unit to determine the part number. Replace the disk unit. This ends the procedure.