DEC Personal DECstation 5000, Руководство пользователя

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Troubleshooting
13.6 Understanding the Powerup Self-Test Sequence and the LED Display
13.6.1 The Power-up Sequence
• Immediately after the system power comes on, the firmware will begin to
execute code.
2 flashes will be displayed. This indicates that the power supply works,
and that portions of the CPU and Base Module are operational.
• The LED then goes dark for about 30 seconds. During this time period the
console code will be loaded into the memory. The system will then identify
what hardware is present, and select which device is to be the default video
console.
Continuous flashes will be displayed if a problem is encountered using
the memory contained on the base module.
When the system reaches the point where text will be displayed on the
default console device, the LED will flash one of two patterns:
2 flashes
indicate that a graphics monitor has been selected.
3 flashes
indicate that the RS232 port has been selected.
• The LED then goes dark a second time for about 30 seconds. The power-up
self-test diagnostic is executed. At this point, status and error messages
will be displayed on the console device.
When the self-test is complete, the LED will be
turned on and will stay
on .
Figure 13–2, Table 13–4, Table 13–5, and Table 13–6 contain additional
information which you may find useful when troubleshooting with the system
LED.
13–10 Troubleshooting