5
System Troubleshooting and Diagnostics
This chapter provides troubleshooting information for the two primary
diagnostic methods: online, interpreting error logs to isolate the FRU; and
offline, interpreting ROM-based diagnostic messages to isolate the FRU.
In addition, the chapter provides information on testing DSSI storage devices,
using MOP Ethernet functions to isolate errors, and interpreting UETP
failures.
The chapter concludes with a section on running loopback tests to test the
console port, embedded Ethernet ports, Embedded DSSI buses, and Q–bus
modules.
5.1 Basic Troubleshooting Flow
Before troubleshooting any system problem, check the site maintenance log for
the system’s service history. Be sure to ask the system manager the following
questions:
• Has the system been used before and did it work correctly?
• Have changes (changes to hardware, updates to firmware or software) been
made to the system recently?
• What is the state of the system—is it online or offline?
If the system is offline and you are not able to bring it up, use the offline
diagnostic tools, such as RBDs, MDM, and LEDs.
If the system is online, use the online diagnostic tools, such as error logs,
crash dumps, UETP, and other log files.
Four common problems occur when you make a change to the system:
1. Incorrect cabling
2. Module configuration errors (incorrect CSR addresses and interrupt
vectors)
3. Incorrect grant continuity
System Troubleshooting and Diagnostics 5–1
