Sun Microsystems SPARCstation 4, Service Manual

Page: 69 / 190

7-1
C H A P T E R
7
Internal Access
This chapter describes how to access the subassemblies inside the system unit, and
how to close the system unit after you have finished.
■
“Removing the Cover” on page 1
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“Attaching the Wrist Strap” on page 3
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“Replacing the Cover” on page 4
7.1 Removing the Cover
Caution –
The AC power cord should remain attached between the system unit and
an AC wall outlet. This connection provides the ground path necessary to protect
internal system components from harmful static discharges. Inside the system unit,
be sure that the power supply wiring harness is connected to the main logic board to
complete the ground.
Caution –
The surface of the microSPARC II chip may be hot and could cause
personal injury if touched. Avoid contacting this component.
Caution –
Before opening the system unit, make sure that the system power is in
the Standby mode. The LED on the front of the system unit should not be lit, and the
fans should not be running. When the system power switch is in the Standby mode,
and the AC power cord remains connected to a power outlet, hazardous AC voltage
is still present in the power supply primary. Do not attempt to service the power
supply under these conditions. Disconnect the AC power cord prior to handling the
power supply. When servicing any other system component, the AC power cord
should remain connected; it poses no safety hazard.