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01
GENERAL
01 .Ol
Thus section
describes
the maintenance
procedures
used for the diagnosis
of faults
in this
electronic
key telephone
system.
Faults are clas-
sified and then cleared
by replacing
the apparatus
and
performing
operational
tests
in the
se-
quences
prescribed
by the
fault
clearing
flow-
charts in Paragraph
05.
02
FAULT
CLASSIFICATION
02.01
A Fault
Classification
Flowchart
is pro-
vided to ensure
that fault clearing
is pursued
in a
logical sequence
(Chart No. 1).
02.02
An assumption
is made in the flowcharts
that the fault
was discovered
and reported
by an
EKT user. All faults,
therefore,
are classified
ac-
cording
to the way they would
appear
at the EKT.
T'
02.03
Faults
and associated
flowcharts
in Ta-
ble A are organized
into the following
categories:
TABLE A - FLOWCHARTS
Flowchart
Title
1
Fault Classification
2
Power Faults
3
Station Faults
4
HKSU Faults
5
CO Line Faults
6
MOH Faults
7
Page/BGM
Faults
8
Door Phone Faults
9
SMDR Faults
10
OPX Faults
11
OPL Faults
12
Reynote Maintenance
Faults
03
FAULT
CLE.ilR:!.dG
PROCEZURES
03.01
Before
attempting
to clear any fault, en-
sure that it is in the system and not caused by as-
sociated
external
equipment,
such
as wiring,
MOH source,
etc.
IMPORTANT!
Many system
features
are assigned,
enabled
or disabled
using
software
entries
as de-
scribedin
Programming
Procedures.
Further,
with the exception
of
Programs
5XX - SXX,
programming
changes
are not effective
until
the new
data has been secured
in working
memory
(see
Paragraph
02.06
of
Pro-
gramming
Procedures).
lt is important
to
verify that
the system
programming
is cor-
rect and functional
before
troubleshooting
the hardware.
FAULT FINDING
SECTION 500-036-500
JANUARY
1988
03.02
In new systems, or when the SCCU/VCCU
PC6 has been changed,
the initialization
procedure
must be performed
before testing. The system data
stored on the original SCCU/VCCU
will be protected
from loss by the backup battery on that PCB. There-
fore, the initialization
sequence
should not
be per-
formed
if the original
PCB is reinstalled.
03.03
Faults
in the system
are cleared
by re-
placing
PCBs, EKTs or the power
supply,
as tn-
strutted
in the flowcharts.
03.04
Five symbols
are used in the flowcharts,
which
are identified
in Figure 1.
Start
and
end
of
a
flowchart
sequence
c3
Important
notes
af-
fecting
the
fault
clear-
----
ing procedure
EI
Question
to
be
an-
swered
YES or NO
0
Progression
TO
or
FROM
another
flow-
chart
location.
Let-
ters
will
denote
exact
entrance
or exit
0
point
Statement
of
a
re-
quired
action
FIGURE
1 -FLOWCHART
SYMBOLS
03.05
The
flowcharts
are
sequentially
ar-
ranged to permit rapid fault localization
within
the
system.
All fault
clearing
must
begin
with the
Fault Classification
Flowchart,
which
is arranged
in the correct fault locating
sequence.
03.06
The following
precautions
must
be ob-
served when
handling
PCBs.
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