Sun Microsystems 6.0005E+11 사용자 설명서
6-2
Ultra Enterprise 6000/5000/4000 Systems Manual—November 1996
6
6.1 Handling Boards and Assemblies
Caution – The chassis AC power cord must remain connected to ensure a
proper ground.
proper ground.
Caution – The clock board and its modules have surface-mount components
that can be broken by flexing the board.
that can be broken by flexing the board.
To minimize the amount of board flexing, observe the following precautions:
•
Hold the board only by the edges near the middle of the board, where the
board stiffener is located. Do not hold the board only at the ends.
board stiffener is located. Do not hold the board only at the ends.
•
When removing the board from an antistatic bag, keep the board vertical
until you lay it on the Sun ESD mat.
until you lay it on the Sun ESD mat.
•
Do not place the board on a hard surface. Use a cushioned antistatic mat.
The board connectors and components have very thin pins that bend easily.
The board connectors and components have very thin pins that bend easily.
•
Do not use an oscilloscope probe on the components. The soldered pins are
easily damaged or shorted by the probe point.
easily damaged or shorted by the probe point.
•
Transport the board in an antistatic bag.
•
Be careful not to drag boards across surfaces as board components are easily
damaged.
damaged.
6.2 Clock Board
There is one clock board to a system. The clock board provides:
•
Programmable system and processor clock
•
Serial, keyboard, and mouse ports for the console
•
Centralized Time-of-day (TOD) chip that includes NVRAM
•
Centralized reset logic
•
Status and control of power supplies
The clock board consists of the following subsystems:
•
Console Bus
•
Clocks
•
Reset logic
•
JTAG
•
Centerplane connector signals
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