INDIRECT VIEW DISPLAY (IVD) 2A1A3 WITH OSA
INPUT CODE: IVDST
This module tests the ability of the indirect view display (IVD) 2A1A3 to
produce correct outputs in response to function commands.
An error detected during any of the following checks will display a prompt at
the completion of the test.
The optical signal analyzer (OSA) chassis to shield continuity is checked for
10 ohms or less.
The OSA shutter interlock operation is verified by checking the
shutter status with the OSA door open (shutter closed).
The operator closes the OSA door, the shutter is programmed open, and shutter
The internal and external relays 1 through 4, phase A, B, and C
contacts are checked for a closed condition.
The operator opens the OSA door and
the OSA shutter is checked for a closed status.
The internal and external relays 1
through 4, phase A, B, and C contacts are checked for an open status.
The operator applies pressure to OSA door interlock switch S1 while OSA door
interlock switch S2 is checked for a shorted condition.
The operator then releases
S1 and applies pressure to S2 while S1 is checked for a shorted condition. The
operator then releases S2 and closes the OSA door. The OSA door status is checked.
The IVD is then programmed to produce a vertical output pulse and a horizontal
output pulse, which are checked for period and amplitude.
REPLACEMENT PROCEDURE REFERENCE
The following list provides a cross reference of replacement items to
The item column identifies the item to be replaced by
reference designation and part number.
The reference column identifies the
procedural paragraph used to perform the replacement action. The VDT screen will
display the proper sequence of repair/replace actions.
(Ref Des/Part No.)