IBM 5251 Series Maintenance Information Manual page 155

212
(continued)
Mini-MAP example
Is the signal present at the driver?
Y N
Is the line at a Down level?
Replace the driver.
The line could be either grounded or logically driven
to the Down level by the driver.
- Check for a ground.
Is the line grounded?
V N
- Replace the driver.
Replace the FRU that caused the ground.
Note: A pull-up resistor at the receiver will cause an Up
level at the receiver if the cable is open.
Is the signal present at the receiver?
Y N
- Repair or replace the interposer or cable.
Is this the last signal line to be checked?
V N
Go through the same procedure for any other lines
called out by the MAP.
Replace the receiver.
212
Suggested action for an intermittent problem:
• Analyze the suspected line; inspect all the connector
contacts.
• Replacement sequence:
FRU A
- FRU B
Note: The FRUs are listed in the order in which they
should be replaced.
Maintenance Procedures 5251 M 1M 137