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1269 User Manual
Understanding The 1269 6-4
Backplane
Interconnections
The Power On/Standby switch (S100) connects to the
backplane through a polarized locking wire-to-board header at
J54.
The optional front panel display module and the temperature
monitor board connect to the backplane through a 24-pin
ribbon cable IDC header at J50.
The module cooling fan connect to the backplane through a
polarized locking wire-to-board header at J56.
The power supply mates with the backplane through board-to-
board connector J52.
The monitoring system module mates with the backplane
through a board-to-board connector at J51.
Cooling System
The module cooling fan is located at the bottom rear of the
mainframe (bench top configuration). The speed of the fan is
controlled to maintain a temperature rise of
#
10
E
C across any
module slot in the mainframe. In high ambient temperature
conditions of
$
40
E
C, the fan shall run full speed.
Rack Mount Cooling
System
Module cooling air enters at the rear of a 1269 rack mounted
mainframe and is filtered as it is drawn through the fan
chamber.
The incoming air is forced into a pressurized plenum on the
P2 side of the VXI modules. The high pressure in the plenum
forces the air through a metered plate into the P2 connector
side of the VXI modules. The air passing over components in
the modules absorbs heat and exits at the P1 side of the
modules.
The rack mounted 1269 mainframe exhausts module cooling
air at the left side of the mainframe (front view).
Bench Top Cooling
System
Filtered air enters at the bottom rear of a 1269 bench top
mainframe through the fan chamber.
The incoming air is forced downward into a pressurized
plenum below the VXI/VME modules. The high pressure in the
plenum forces the air up through a metered plate into the
VXI/VME modules. The air passing over components in the
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