This chapter describes troubleshooting procedures for the GT Graphics Subsystem . The procedures described in this chapter have been written with the assumption that you have already isolated the problem to the GT Graphics Subsystem or at least to a display problem and not a CPU, software, or network problem.
The basic steps to isolating and fixing a problem with the GT Graphics Subsystem are as follows:
If possible, ask the customer to run the GT internal self test (see "Running the Internal Self Test" on page 38) and report the diagnostic LED status. These indicators may tell you the most-likely failing FRU (see Table 3-1 on page 40).
If the customer can run this test and report the results to you over the phone, you will have a better idea of what spares to bring with you when you go to the site.
Note - Since the monitor itself is the most-common component to fail, ask the customer to take a look at the monitor for obvious signs of trouble:
Figure 2-1 Initial Fault Analysis
Based on the reported symptoms, attempt to verify the problem with the possible solution in Table 2-1.
Table 2-1 Symptom Analysis Guide
Table 2-1 Symptom Analysis Guide (Continued)
Verify that the reported problem is repeatable. Attempt to duplicate the failure reported by the user. In some cases, this process will isolate the FRU, but in other cases of more subtle problems, you may be able to gather more symptoms that confirm the failure. In some cases the problem is obvious and is found during the verification phase.
For example, the user may report smoke coming from the monitor and when you turn on the power to verify it, sure enough there is smoke. You have already isolated the faulty FRU.
On the other hand, the user could report that something smells like burning insulation. You turn on the power and sure enough you can detect the faint odor of burning insulation, but the source is not obvious. Now you have to isolate the part of the system causing the smell.
Figure 2-2 Verify the Problem
In the isolation process, you identify the root cause of the problem. For example, when the user reports that the screen blanks intermittently, you verify by attempting to re-create the failure symptom and then you isolate the problem to a FRU.
To isolate the problem to the FRU level, use the diagnostics (described in Chapter 3).
Figure 2-3 Isolate the Failing FRU
Figure 2-3 Isolate the Failing FRU (Continued)
Once isolated, repair or replace the FRU. See the subassembly removal and replacement procedures in Chapter 4.
Caution -
Figure 2-4 Repair or Replace the FRU
After replacing the FRU, use the internal self test or SunDiag diagnostics (Chapter 3) to test the replaced FRU. Also, attempt to re-create the original problem to make sure that you have isolated all the failing FRUs.
