Product manual

Maintenance, Fault finding procedures

Technical Product Manual - DCT1800-GAP

TD 92093 (1/LZBNB 103 108 R4D) / 2006-03-09/ Ver.C

Chapter 6 Fault finding procedures

6.1 Introduction

These fault finding procedures are designed to help maintenance personnel locate and eliminate faults

in the shortest possible time. The fault finding extends to the level of a replaceable product (LTU, SPU,

power supply unit, etc.). Although cabling and connection errors are not covered, suggestions will be

given to check these items when the fault is presumed to be introduced by them. The basic assumptions

for the fault finding are:

• Only one fault at a time

• The fault is permanent (not intermittent)

• Fault is not due to cabling or bad connections

The execution of the following steps will avoid unnecessary fault locating:

• Analysis of the fault symptoms

• Visual inspection of the system (cabling, connections, power cords)

If these steps do not solve the fault, the flowcharts given in paragraph 6.4 can be used.

6.2 Symbols used in the flow charts

This symbol contains a question with two or three possible answers being

yes (Y), no (N) or text.

Inputs are points 1 or 4 and outputs are points 2 or 3 or 4.

This symbol contains an instruction for the maintenance engineer.

This symbol is used as: starting point for a procedure (e.g. START), as a

reference to another flowchart, to end a procedure (END)

This symbol is used as reference within one flowchart. This can be to a part

of the flowchart on another page (e.g. B or C) or at a part of the flowchart

on the same page (e.g. 1).

Lines indicate the normal flow. The normal flow is always ‘down’ and ‘to the

right’.

Arrows are used to indicate flows going ‘up’ or ‘left’

Question

Question?

Instruction

References

Flow