Appendix G: Example MTTR Procedures

G.1 Mean Time to Repair (MTTR)—Rack-Mounted PC chassis

The following examples are typical illustrations of the time to replace mechanical components in a 19-inch rack-mounted PC chassis. All times assume that fault isolation has taken place. Total times listed include boot time, estimated at 1 minute and 30 seconds (i.e., the time required for the unit and software to become fully operational after the repair is complete). All testing was done with a unit rack-mounted at approximately 5 ft.

G.1.1 Replace PCI Network Interface Card (NIC)

Procedure

• Open chassis (2 screws and slide chassis out)

• Remove brace (2 screws)

• Remove NIC (1 screw)

• Reboot system

  Total Time = 4 min 30 sec (3 min repair + 1 min 30 sec reboot)

G.1.2 Replace power supply

Procedure

• Power supply removes from rear of unit (2 screws)

• Reboot system

  Total Time = 2 min 30 sec (1 min repair + 1 min 30 sec reboot)

G.1.3 Replace CDROM or floppy drive

Note that the procedure and times were essentially the same for both the CDROM and the floppy drive.

Procedure

• Open chassis (2 screws and slide chassis out)

• Remove CDROM/floppy assembly (2 screws)

• Remove CDROM or floppy (4 screws)

• Reboot system

  Total Time = 7 min (5 min 30 sec repair + 1 min 30 sec reboot)

G.1.4 Replace FAN assembly

Procedure

• Open chassis (2 screws and slide chassis out)

• Remove FAN assembly (1 screw and slide up)

• Remove power cable to motherboard

• Reboot system

  Total Time = 4 min 30 sec (3 min repair + 1 min 30 sec reboot)

G.1.5 Replace hard disk drive and restore database

For this failure the time to reload software and restore a database was added to obtain the actual repair time.

Procedure

• Replace drive (7 min 45 sec)

• Reload OS software from CDROM (6 min 45 sec)

• Restore database from floppy and reboot (2 min 30 sec)

  Total Time = 16 min 20 sec