Chapter 9 Troubleshooting; Section Introduction; General; Test Procedures - Motorola MTM800 User Manual

TROUBLESHOOTING

Section Introduction

General

Troubleshooting faults in the terminal require proper understanding of the different circuitry con-
tained in the terminal. Since the terminal contains a highly integrated system, the software and hard-
ware functions can not be separated easily. Thus, it is also necessary to understand the functioning
of different ICs and the role of the software in the operation of the terminal. This service manual
includes schematic diagrams, circuit board layouts, block diagrams, and troubleshooting proce-
dures, which help a technician to troubleshoot a malfunctioning circuit and detect a defective com-
ponent.
NOTE: The CPS has no capability to tune the terminal. Tuning the terminal can only be performed
at the factory or at the appropriate Motorola Repair Centre.
Components replacement can affect the terminal tuning and must only be performed by
the appropriate Motorola Repair Centre.
The terminal is tuned and tested at the factory. The results of the tuning procedures are stored in a
special area of the Flash PROM. This information includes tuning and other system parameters. The
area of the memory in the terminal where the tuning information is stored is called the "codeplug". A
terminal codeplug can be read using the CPS programme.

Test Procedures

This section explains the procedures required to troubleshoot an MTM800 ENH terminal. Whenever
possible the terminal should be tested and tuned using the automatic test system PATS before trou-
bleshooting. The PATS result file can provide useful hints to determine the failing circuitry section.
Alternatively, the Main Function Test Procedure can be performed to determine where to start trou-
bleshooting. After disassembling the board from the chassis you should check the board visually for
bad soldering or damaged components.

Troubleshooting Setup

Some of the troubleshooting procedures require an audio signal input or measurement of the audio
at the speaker output. The Test Set RLN4460 provides the correct microphone input and speaker
output circuitry. Figure 1 shows the recommended setup for troubleshooting. Figure 2 shows the
required connections between the terminal's accessory connector, the Test Set and the Interface
Box. The Interface Box GMCN1019_ connects the terminal to the RS232 interface of a PC and is
required to control the terminal during troubleshooting.
If the terminal is connected to the power supply and the Interface Box the green LED at the Interface
Box should light up only. If the red LED lights up as well toggle the switch at the Interface Box and
restart the procedure.
TROUBLESHOOTING
9 - 1
CHAPTER 9