Sun Microsystems Ultra 5, Service Manual

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Chapter 3 Power-On Self-Test 3-23
3.7 Initializing Motherboard POST
To initialize the motherboard POST:
1. Power off the system.
2. Simultaneously press and hold the Stop and D keys, then press the Standby
(Power) key (
FIGURE 3-2
or
FIGURE 3-3
).
Note – Video output is disabled while motherboard POST is initialized.
Note –
To view the POST output results, you must set up a TIP connection. See
Section 3.2.1 “Setting Up a TIP Connection” on page 3-2.
3. Verify the keyboard Caps Lock key LED flashes on and off to indicate the system
has enabled POST.
4. If a failure occurs during POST, a keyboard key LED other than the Caps Lock
key LED might light, indicating a failed system component.
See Section 3.4.3 “POST Progress and Error Reporting” on page 3-19.
Note – The most probable cause of this type of failure is the motherboard. However,
optional system components could also cause POST to fail.
5. Before replacing the motherboard, remove any optional components, such as PCI
cards, then repeat the POST.
Note – Non-optional components such as DIMMs, the motherboard, the power
supply, and the keyboard must be installed for POST to execute properly. Removing
the optional system components and retesting the system isolates the possibility that
those components are the cause of the failure.