Chapter 14 - Fault Finding; Fault Classification; Fault Clearing Procedures - Toshiba STRATA DK14 Installation And Maintenance Manual

Fault Finding
This chapter describes the procedures to diagnose faults in the Strata DK14 and DK40i Key
Service Unit (KSU) as well as the DK424 and DK424i systems. Faults are classified and then
cleared by replacing the malfunctioning unit and by performing operational tests in the sequences
by prescribed by the fault clearing flowcharts in

Fault Classification

A Fault Classification Flowchart is provided to ensure that fault clearing is pursued in a logical
sequence (Flowchart 14-1 on Page
The flowcharts assume that the fault was discovered and reported by a digital or electronic
telephone user. All faults, therefore, are classified according to the way they would appear at the
digital or electronic telephone.

Fault Clearing Procedures

Before attempting to clear any fault, ensure that it is in the system and not caused by associated
external equipment, such as wiring, MOH source, etc.
Important! Many system features are assigned, enabled or disabled using software entries as
described in the Strata DK Programming Manual. It is very important to verify that
the system programming is correct and functional before troubleshooting the
hardware.
Initialize the system (Programs 91-9 and 03) before testing new systems or when changing the
DK14 or DK40i KSU, or DK424 or DK424i processor PCBs.
Strata DK I&M 6/00
"Fault Isolation Flowcharts" on Page
14-10).
14
14-10.
14-1