IBM 3745 Maintenance Information Reference page 188

Checking Adapter Buses
Introduction
Initial Conditions
Procedure
This procedure allows isolating short or open circuits in adapter bus circuits
and terminator cards (ITER, OTER, STER).
SACU Board LA Board
IOSt~
Card LA card
Adapter Bus
L
Connector
o
0
on SACU board
STER Card
fr
Top Connector
ITERjDTER Card
To
ground
Before starting the checks, you must:
1. Power the 3745 OFF.
2. Unplug all the adapter cards, and the L TC1 and L TC2 cards on the CA
board{s).
Depending on the bus to be checked, use one of the following pages to
measure the resistor value.
To
ground
Measurement is performed between each referenced pin and the ground pin.
o
ITER/OTER, adapter bus cables, STER continuity:
This check is performed on the ITER/OTER card top connector with all adapter
cables plugged.
o
ITER/OTER and adapter bus cables check:
Same procedure as above, but the adapter bus cables are not plugged on the
SACU board.
Il
Adapter bus cable and ITER/OTER continuity:
This check is performed on the connector of the adapter bus cables on the
SACU board side (the adapter bus cables are unplugged from the SACU board).
Chapter 3. Buses and Bus Switching
3-85