ATT System 25 Maintenance Manual

MAINTENANCE STRATEGY
Figure 5-1. Response to System 25 Trouble Report
5-2 

MAINTENANCE STRATEGY
General Procedures
Sometimes, faults recorded in the error log and user-reported troubles will
exist at the same time. The logged faults should always be cleared first, if
possible. This procedure often clears the user-reported troubles without any
additional maintenance.
Clearing the most serious logged fault may clear some or all of the other
faults. Descriptions of the errors in the error log indicate their relative
urgency.
Error log records should be manually recorded before...

MAINTENANCE STRATEGY
Common Control Problems
Common Control circuitry is difficult to troubleshoot and replace. The system
must be powered down before any of these CPs are replaced. Before
powering down, translations should be saved to tape (see Section 7
Operating the Digital Tape Unit). Other repair procedures may also require
the system to be powered down. After removing a suspected faulty CP, do
the following
l
l
lVisually inspect the CP. If a problem is identified, attach a note to the
CP...

MAINTENANCE STRATEGY
Automatic Maintenance Tests
Because System 25 maintenance tests are performed automatically, there is
no provision for users or technicians to initiate maintenance tests. The error
log is read by entering commands from the SAT. Additional information that
may be of help in clearing complex or subtle troubles is also available via the
SAT (for example, the record of port locations).
Refer to Administration Manual (555-520-500) for your system for information
on using Search procedures...

ERROR LOG
The error log is accessible via the System Administration Terminal (SAT)
using the following procedures. The Error Log is comprised of the following
three error tables:
lPermanent System Alarms
lTransient System Errors
lMost Recent System Errors.
Each error record is reported as one line on the SAT (80 characters or
fewer). Permanent System Alarms and Transient System Errors tables use
the same format. These error records provide the location of the error [by
port and circuit pack (CP) type],...

ERROR LOG
lLast Occurred 30/01:56 is the date and time of the last occurrence of
this error. The date is assumed to be the current year and month. A
24-hour clock is used.
lCount 6 is the number of times this particular error has occurred.
lName System Restart is a description of the nature of the error.
Descriptions are self-explanatory.
Error records in the Most Recent System Errors table have a slightly different
format. A typical error record from the Most Recent System Errors table is
as follows:...

ERROR LOG
The error log is under the control of internal background maintenance
software that automatically escalates an error to a more serious category or
retires it. The system tests itself after a repair has been made. If the error
condition is corrected, the error may be removed from the error log.
Although some errors are automatically retired from the error log, they can
also be manually retired by entering commands at the SAT. Alarms,
conditions that light the alarm light-emitting diode (LED) on...

ERROR LOG
8.The SAT displays:
When search is defined type c to search >Action=
9.Enter 1 and .
10.
11.
12.The SAT displays:
SEARCHES: ACTION=1 DATA=
Enter D. The system completes the word Data followed by the =
sign.
After Data= enter one of the following numbers, depending on which
error table you wish to see:
l 30 to see Permanent System Alarms
l 31 to see Transient System Errors
l 32 to see Most Recent System Errors.
If you select 30, for example, the system responds with: SEARCHES:
Action=1 Data=30....

ERROR LOG
Error Log Dictionary
The following provides a listing of error messages displayed on the SAT and
an associated description of each.
AC Power Failure: An indication that ac power has been lost (for example,
plug removed from a wall receptacle, building power down, etc.)
Alarm Log Overflow: The error logs are full and no more errors can be
written to them. This error is kept, however, to alert you of the fact.
Arch Angel Insane Restart: Clocks may be missing from the TDM bus. Make
sure TDM bus...

ERROR LOG
Bad Port Translations: Service Circuit or Tone Detector. Receiver requested
to listen to time slots that do not have tones on them. System may recover
from this error.
Bad Ringing Supply: Problems detected with ringing portion of power
supply.
Bad Sub Qualifier: (Other than CPU or Memory) Invalid message type on a
down-link message. System may recover from this.
Belated External Release: See No External Release On PBX Disconnect.
Board Initialization Audit Error: (Other than CPU or Memory)...