Introduction To Diagnostics - IBM 6151 Maintenance And Service Manual

Introduction to Diagnostics
Note: Some system unit components do not cool properly and may
fail intermittently when covers are off. For this reason do not
power the system unit on longer than 10 minutes with the covers
off.
The diagnostic programs are divided into six types:
• The Resident Power-On Self-Test (POST) programs are in
Read-Only Memory (ROM) modules on the processor board.
These programs run when the system unit is first powered on.
The Resident POST programs check the system unit components
needed to load programs from the fixed disk or diskette. See
page 2-6 for more information about the Resident POST
programs.
•
The Loadable POST programs load from the fixed disk or the
diagnostics diskettes. These programs run when the Resident
POST programs complete.
The Loadable POST programs first sense the adapters and
options installed in the system unit and build an Installed
Features List. Before any checkout routines are run, the
installed features list is compared to the Configuration Record
on the fixed disk. See page 2-6 for more information about the
Loadable POST programs.
Pressing the Ctrl-Alt-Pause keys cause the Loadable POST
programs to run.
•
The Diagnostic Routines are on the diagnostics diskettes. The
Problem Determination Guide directs the system user to run the
Diagnostic Routines
to
check the system unit during problem
determination. See page 2-12 for more information about the
Diagnostic Routines.
2-4 Service Manual