Product data
Chapter 3. Removal and Replacement Procedures
Are You Using the Correct Book? Do not use this book if you are servicing a 2104
Model DL1 or TL1. For the correct book, see Related Publications in Appendix A.
Additional Information for RISC Systems.
These instructions describe how to remove field-replaceable units (FRUs) from the
2104.
Each FRU has its own removal procedure, for example, “Fan-and-Power-Supply
Assembly”. Where a step in a specific procedure represents a complete procedure that
is described separately, a reference to that procedure is given. For example:
1. Remove the front cover (see “Cover” on page 68).
2. Remove all the disk drive modules (see “Removing a Module” on page 75).
The references show you where to find more detail, if you need it.
Note: Although these instructions relate to the 2104 Model DU3 and to the 2104 Model
TU3, some diagrams might not specifically show the model that you are
servicing.
Concurrent Maintenance
Subject to the configuration of the 2104, most FRUs can be removed, replaced, and
tested while the subsystem and using system are powered on and doing productive
work. This ability is called “concurrent maintenance”. Unless you have a particular
reason to do so, do not remove the power unless these instructions tell you to do so.
The following FRUs can be maintained concurrently in a 2104 subsystem:
v Fan assembly
v Fan-and-power-supply assembly (if two are present)
v Disk drive module
v Dummy disk drive module
v SCSI Interface card assembly (if the subsystem configuration allows)
v Dummy SCSI Interface card assembly
v Switch card assembly
v External SCSI cables (if the subsystem configuration allows)
The following FRUs cannot be maintained concurrently:
v SCSI bus bridge card assembly
v Frame assembly
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