Nortel DMS-10 Series Installation, Operation And Maintenance Manual page 605

Procedure 6-40
SCSI Crossover PCA replacement (NT6M93BA)
Step Description
40
Loosen the slotted screws which fasten the outer edges of the appropriate rear panel
assembly to the cabinet.
41
Pull the rear panel away from the cabinet. Remove the front panel of the chassis to improve
cooling, if necessary. Put the two panels in a safe place to prevent bending and scratching.
42
Loosen the two screws at the top of the hinged card panel and remove the screw at the
bottom of the hinged card panel. Let it swing slowly down from the top until it rests.
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.
43
Remove power cable (J4), then any cables and screws connected 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 assembly loose from its mounting position.
44
Verify (J5) jumper option is the same on the replacement PCA as the PCA that was
removed.
WARNING
Incorrect positioning of jumper may cause loss of AMA. When replacing the
SCSI Crossover PCA in the A chassis, be sure to place the jumper on pin A
and the center pin. When replacing the SCSI Crossover PCA in the B
chassis, be sure to place the jumper on pin B and the center pin.
45
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.
46
Reattach any cables removed in step 7 in reverse order.
BMC II BISYNC Operation, Administration, and Maintenance Guide BMCB001 and up
Section 060-INDP-610 Maintenance Procedures Guide 6-167
(Sheet 2 of 4)