System Board Test - Sun Microsystems SPARCclassic Service Manual

Power Supply Connector Pin Assignments
TABLE 4–2
Pin Description
4 Ground
5 +12 Vdc
6 POK

System Board Test

1. Connect a terminal to serial port A or use a tip connection to another
workstation to receive additional POST failure information.
To set up a tip connection to another workstation, see "Setting Up a tip
Connection to Another Workstation" on page 24.
2. Press and hold the Stop-d keys. While holding the keys down, turn the system
power switch on. Watch the keyboard LEDs.
a. The Caps Lock key on the keyboard should flash on and off, indicating that
the system is running the Power-On Self-Test (POST).
If the Caps Lock key fails to flash on and off after you have pressed and held
the Stop-d keys, POST failed.
b. To further troubleshoot the system board, see "Caps Lock Key Fails to Flash
On and Off During POST" on page 35.
3. Observe the keyboard LEDs.
If a failure occurs during POST, an LED may light up. Table 3–1 in Chapter 3,
describes types of problems that occur when an LED on the keyboard lights up.
4. Replace the defective part indicated.
Caps Lock Key Fails to Flash On and Off During POST
1. Remove optional SBus cards and SIMMs.
Leave a pair of SIMMs in Bank 1.
2. Run POST again before replacing the system board.
(continued)
Pin Description
10 Ground
11 +12 Vdc
12 -12 Vdc
Troubleshooting Procedures
35