34 Disk Crossover PCA Replacement Procedure (NT6M72xx)
297-6201-501 97Q3 Standard 02.01 July 1997
Note: If the PCA at A15 is being replaced, use a Styrofoam block or
another insulating material, about 1” x 1” x 0.5”, to insulate the pins of
the 16-pin cable on the P/A Comm PCA to prevent accidental shorting
against the chassis.
7 Remove power cable (J4), then any cables and screws con-
nected to the suspected PCA.
Note: Observe the cable markings (identification) or attach labels to the
cables for correct positioning for installation of replacement PCA.
Gently pull the suspect PCA loose from its mounting position.
8 Verify (J5) jumper option is the same on the replacement PCA
as the PCA that was removed.
Note: The J5 jumper on the A chassis Disk Crossover PCA must be
placed on pin A and the center pin. The J5 jumper on the B chassis Disk
Crossover PCA must be placed on pin B and the center pin.
WARNING
Incorrect positioning of jumper may cause loss of AMA.
9 Mount the replacement PCA in the vacated position.
Note: When replacing the screws, align carefully before tightening to
avoid stripping. Tighten the screws, alternating until all are equally tight.
Do not “cinch down” any one screw until all are properly aligned; no
binding or force needed to turn.
10 Reattach any cables removed in step 6 in reverse order.
Note: Verify the cable markings (identification) or attach labels to the
cables for correct positioning.
WARNING
Incorrect positioning of cables may cause loss of AMA.
11 Verify the repair by switching disk modes back to PRIME.
Enter (at the terminal):
>DSK MODE xx (cr)
where: xx - disk mode: AP - A PRIME (if mode is A only)
BP - B PRIME (if mode is B only).
The BMC will begin a disk copy this may take several hours,
depending on how much data and how large the disks are.
Proper response:
DISK MODE: AP (from disk mode AO)
or
DISK MODE: BP (from disk mode BO)
12 Remove the insulating material, if used. Route all wires and
cables to avoid pinching or crimping when the rear panel is
reinstalled.
Procedure 4
Disk Crossover PCA replacement (NT6M72xx)
Step Description
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