Technical data

Dual 9-, 12-, and 20-Slot Chassis
9-5
9
Dual 9-, 12-, and 20-Slot Chassis
Control Board
The control board assembly controls the application of power to the
VME backplane and the routing of alarm signals from the
environmental monitoring system. The assembly consists of the
control board, switch bracket, and keyswitch. It is held in the
chassis by spring-loaded tabs on the switch bracket. 12- and 20-slot
chassis are equipped with a single control board assembly; dual 9-
slot chassis have two of them.
The suggested procedure for the removal and replacement of the
control board assembly is as follows:
Removal
1. Switch the power supply of the affected system to
STANDBY
and disconnect the system from the AC or DC power source:
– If the power supply is an AC unit, unplug the power cord
from the AC outlet.
– If the power supply is a DC unit, turn off the -48Vdc power
source and unclamp the DC leads from the terminal block
on the power supply.
!
Caution
Removing a control board without disconnecting the
power will cause the system to power up even when set
to
STANDBY.
2. Remove the front bezel, if installed.
3. Unclip the control board assembly (Figure 5-3) from the card
cage by firmly grasping the switch bracket and pulling
straight out.
4. Carefully remove the assembly from the chassis by
continuing to pull straight out.