TM 11-5895-856-34-1/ E E640-CA-MMI-010/E 154 CPU/TO 31W2-2T-122-1
remove remaining screws.
push to closed position.
(8) Tighten frame assembly D captive fasteners
(7) Both persons lift out card cage being very
securing frame assembly to cabinet.
careful not to damage rear wiring and pins.
(9) At circuit breaker panel DC group, set
b. Replacement.
PROCESSOR 1 or 2 (MCMU 1B or 2B) to ON.
WARNING
3-18. IFCU Card Cage Removal and Replacement
Replacement of card cage is a two-
The entire IFCU must be shut down when a card cage is
person operation. One must support
replaced. This interrupts operation of the message switch.
cage while the other replaces attaching
However, the circuit switch can continue processing calls
hardware. If card cage is allowed to fall
with the IFCU shut off. Therefore, if possible, such
when hardware is being replaced, back-
procedures should be scheduled into system operation.
plane wire-wrap pins can be bent,
Due to redundant nature of peripheral equipments and
shorted, or broken. Also, wiring may be
partitioning of IFCU circuits it is often possible to continue
damaged.
operation with a reduced complement of equipment until
(1) Both persons life card cage into position.
the repair activity can be conveniently scheduled. A card
First person, hold card cage; second person secure card
cage is replaced with all cards installed (figs. 3-8 and 3-
cage with screws.
9).
(2) Reconnect all ribbon cables.
a. Removal
(3) Reconnect power cables.
WARNING
(4) On circuit switch for A1A4 (IFCU), tighten
Removal of card cage is a two-person
captive fasteners which secure access panel on front of
operation. One must support the cage
hinged door frame A. Close access panel.
while the other removes attaching
(5) On message switch for A1A17 (IFCU) and
hardware. Card cage will drop when
A1A8 (IFCU D), tighten captive fasteners which secure
last two screws are removed. If the
door frame C to cabinet assembly.
card cage is allowed to fall when
(6) On message switch for A1A15 (IFCU A) and
hardware is removed, back-plane wire-
A1A16 (IFCU B), tighten captive fasteners which secure
wrap pins may be bent, shorted, or
hinged door C to door frame C, and close door.
broken. Also, wiring may be damaged.
(7) Set appropriate circuit breakers to ON
(1) On circuit breaker panel set all IFCU circuit
position .
breakers to OFF position.
(2) On ADP status and control panel (figs. 2-7 3-19.
ADP Status and Control Removal and
Replacement
Replacement of the message switch or circuit switch ADP
indicators/switches are OFF.
(3) Gain access to card cage by opening status and control panel (figs. 2-7 and 2-8) requires
shutting down entire ADP assembly, and, therefore, an
appropriate door:
(a) On message switch for A1A15 (IFCU interruption to the operation of the switch.
a. Removal
A) and A1A16 (IFCU B) (fig. 3-8, sheet 4), loosen captive
(1) On circuit breaker panel set the following
fasteners which secure hinged door C to door frame C.
circuit breakers to OFF position:
Pull door open.
(a) PROCESSOR 1 (four circuit breakers).
(b) On message switch for A1A17 (IFCU
C) and A1A18 (IFCU D) (fig. 3-8, sheet 4), loosen captive
(b) PROCESSOR 2 (four circuit breakers).
fasteners which secure door frame C to cabinet assembly.
(c) IFCU (four circuit breakers in message
(c) On circuit switch for A1A4 (IFCU) (fig. switch, one circuit breaker in circuit switch).
(2) Loosen ten captive fasteners which secure
access panel on front of hinged door frame A. Swing hinged portion of panel. Swing panel open.
access panel open.
(3) Disconnect all ribbon cables from panel.
(4) Using card extractor, disconnect all ribbon
(4) While holding panel, remove screws which
cables from card cage.
secure panel to door and remove panel.
(5) Disconnect power cable from card cage.
b. Replacement.
(6) Remove all but two screws (on opposite top
(1) Hold up panel to door and secure with
corners) which secure card cage. First person, hold card
screws.
cage to assure it will not fall; second person,
(2) Connect all ribbon cables.
(3) Secure panel with captive fasteners.
(4) Set all circuit breakers to ON position.
3-32
TM 11-5895-856-34-1/ E E640-CA-MMI-010/E 154 CPU/TO 31W2-2T-122-1
Previous Page
