Probing Information When Using Maps; Normal Conditions After Power On - IBM 5280 Manual

How to Use the MAPs
You should observe the following rules and procedures
when using the MAPs or running MOl tests:
1.
2.
3.
4.
When any MOl tests are to be run, the MAP
describes how to set up the machine in the correct
condition to answer the MAP questions.
Before starting the error analysis, always observe
and record any existing error symptoms.
The MAP might send you to the MIM for
instructions on how to remove, check, adjust, or
reinstall a FRU. After completing the action, return
to the MAP for additional instructions.
If the failure symptoms do not remain constant,
you should still attempt to use the MAPs and MOl
tests to isolate the failure.
5. Unless you are instructed not to, always power off
the system before you remove or install a fuse,
cable, or card.
6.
When a MAP indicates that a card or cable is bad,
perform the following steps:
a. Inspect the card and socket, then res eat the
card and rerun the test that failed.
b. Remove the card or cable, install a good one,
and rerun the test that failed.
7. Probe all the "lines indicated before answering the
question that follpws in the MAP or MOl test.
8. Names of all switches and indicators are shown in
MAPs in the same way that they appear on the
keyboard/display or operator panel.
9. Hexidecimal numbers are shown as hex AB23.
10. An X indicates a don't care position within the
number. For example, the X In hex X54B
represents any hexadecimal number.
11. After you diagnose and repair a failure, run the
failing MAP or MOl test again to verify that the
failure is corrected.
Probing Information When Using MAPs
When instructed by the MAPs, you should use the
general logic probe" (part 453212) to measure signal
levels. This probe is used for normal IBM 5280
Distributed Data System maintenance. The probe
extender (part 453605) is used with the general logic
probe in all MAPs except where you are instructed to
use the short probe tips. Detailed information on using
and maintaining the probe is found in the IBM General
Logic Probe /I Manual, SY27-0127, and in the Diagnostic
Aids section (see 905) of the IBM 5285 Programmable
Data Station Maintenance Information Manual,SY31-0600.
Normal Conditions After Power On
After you have powered on the system, the following
display examples show the normal conditions of the
display screen on the IBM 5285. All other attached data
stations or dual data stations are blank.
The selected program diskette must be inserted into a
diskette drive and the diskette locking lever must be
closed.
If the selected program diskette is inserted into an
attached data station diskette drive, that data station
must also be powered on.
MAP Introduction xiii