Digital Equipment EK-SFXXS-SG-003, Руководство по обслуживанию

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SF7x Storage Enclosure FRU Replacement 6–35
6.5 Replacing the Transition-Termination Module
Use the following procedure to remove and replace the transition-
termination module (TTM) (PN 54–19081–01):
1. Perform an orderly shutdown of the host system and
all devices on
that bus. Remove ac power to the host system(s).
2. Access the storage enclosure by opening the cabinet doors.
3. Take the disk ISEs in the storage enclosure off-line:
a. Press and release all Ready buttons on the OCP (Figure 6–2).
Wait for the Ready LEDs to go out.
b. At the lower front of the storage enclosure, set the drive dc power
off (Figure 6–2). The switch element LEDs should go out to
indicate that power has been removed from the disk ISE. If any
LED does not go out, suspect a faulty switch.
4. At the rear of the storage enclosure, turn off the enclosure with the ac
power switch at the rear of the power supply.
CAUTION
Wear an ESD grounding strap at all times while handling the
storage enclosure or any of its FRUs.
5. Remove the OCP—grasp it firmly and pull it straight out. Do not pry;
the panel comes free with a straight pull.
6. Loosen the four captive hex-head screws at each corner of the
enclosure frame and, from the rear, push the inner assembly partially
out of the enclosure.
WARNING
Take care when accessing the internal components of the
inner assembly. A stop mechanism in the chassis locks
the inner assembly at a point that allows access to the fan
assembly. This stop mechanism locks the chassis so that the
inner assembly is over three-quarters of the way out of the
chassis. If you release this stop, nothing prevents the inner
assembly from being pulled completely free of the extrusion
tube.
7. Disconnect all the cables from TTM.
8. Carefully unseat the TTM from the nylon posts. Use a flatblade
screwdriver to release the locking tabs.