FRU Exchange
Chapter 4. 3745 FRU Exchange
This chapter is to be used to exchange a defined FRU. Use all section from the begining to the end, to
determine:
1. Where the FRU is physically located
2. How to properly exchange FRUs
3. How to test the machine
4. What else must be done before returning the machine to the customer.

Exchange Precautions

1. Most of the 3745 FRUs can be exchanged in concurrent maintenance. Thus, it is very important that
these procedures be followed when replacing any FRU in the machine.
2. The control panel has voltage present even with the machine Powered OFF.
3. Ensure that the 3745 is powered OFF before replacing any FRUs, except for hot-pluggable FRUs
(LIC,MUX) and the separated power-controlled FRUs (FDD and HDD).
4. Before starting the FRU exchange, ensure that the involved area has been disabled by the cus-
tomer.
5. The 3745 Communication Controller contains cards that are sensitive to electrostatic discharge (ESD).
Use the ESD kit and store all cards in their protective packaging when you are not actually exchanging
them.
6. Procedures for exchanging FRUs are listed on the next pages. Use the list in alphabetical order.
7. After the 3745 FRU exchange, go to “Action to Take After a Diagnostic Run or an FRU Exchange” on
page 4-99.
Attention
Do not disassemble or attempt to remove FRUs from the 3745 until you have read the Safety Infor-
mation manual, GA33-0400.
Very important
Ensure that the required area has been disabled
before any FRU exchange
if not, go to start page and follow the appropriate procedure.
Copyright IBM Corp. 1989, 1997 4-1