Removing The Main Logic Board - Sun Microsystems SPARCclassic Service Manual

Removing the Main Logic Board

This section explains how to remove a faulty main logic board from the system unit.
Note -
"Before Replacing the Main Logic Board" on page 128 for troubleshooting
information.
To remove the main logic board:
1. Prepare to work on the system as described in Chapter 6, and in Chapter 7.
Halt the system and verify that the power LED is not lit and that the fan is not
running. Then open the system unit, detach all peripherals, and attach a wrist
strap as described in "Attaching the Wrist Strap" on page 53.
Caution -
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 the power supply wiring harness is connected to the main logic board to
complete the ground.
Caution -
LED at the front of the system unit should not be lit and the fan should not be
running. When the system power switch is in the Standby position, 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 and poses no safety hazard.
2. Place an antistatic mat, shiny side down, next to the system unit.
3. Remove any SBus cards.
See "SBus Cards" on page 107 for removal procedures.
4. Remove all DSIMMs from the main logic board.
Note carefully the slot where each DSIMM resides so it may be installed in the
same slot on the replacement main logic board. See "Removing a DSIMM" on
page 120, for removal procedures.
SPARCclassic/SPARCclassic X/SPARCstation LX Service Manual ♦ Revision A, November 1993
132
Removing and replacing the main logic board is a drastic step to take. See
The AC power cord should remain attached between the system unit and
Verify that the system power switch is in the Standby position. The green