Introduction; Purpose; Description; General - Motorola Handie-Talkie MTX Series Theory/Troubleshooting Manual

I.

PURPOSE

This manual will provide a theoretical explanation of
the HT 1000, MT 2000, MTS 2000, and MTX Series
portable radio's operation, troubleshooting, and addition-
al useful information about the radio not found in
any other publication. The manual is divided into three
sections:
•

INTRODUCTION

• THEORY OF OPERATION
• TROUBLESHOOTING
In the THEORY OF OPERATION section, a basic
functional description is followed with a more detailed
description of some selected circuits. All applicable fre-
quency bands are covered in this publication.
A complete list of models and each model's descrip-
tion is provided in a separate service manual. A detailed
description of the radio's operational features, a list of
applicable batteries and accessories, and a section on
general radio information is provided in several operat-
ing instruction manuals. To help you with your selection,
a complete list of the other publications on HT 1000, MT
2000, MTS 2000, and MTX Series portable radios can
be found following the Table of Contents of this manual.
II. DESCRIPTION
A. General
The HT 1000 Handie-Talkie portable radio is a
microcomputer-based, single-mode (conventional)
transceiver. The MT 2000, MTS 2000, and MTX Series
Handie-Talkie portable radios are microprocessor-based
dual-mode (trunked/conventional) transceivers. In all of
the radios, the microcomputer determines the active
state of the radio (transmit/receive), monitors radio sta-
tus, and processes operator commands entered from
the keypad (if applicable) or the other radio controls.
INTRODUCTION
Various switches, buttons, knobs, and indicators are
ergonomically designed, making placement in strategic
locations on the different model radios. Refer to the spe-
cific operating instructions on your radio for location and
description of these controls. All of the controls, includ-
ing the push-to-talk (PTT) switch and key pad
(if applicable) are weather resistant. The microphone
and speaker are covered by a diaphragm for additional
protection.
B. Printed Circuit Boards and Flexible Circuits
Most of the radio circuitry is contained in chip carri-
ers that are mounted on one of the two rigid, printed
circuit boards (PC boards); the controller board and the
transceiver board. Front display model radios contain a
third rigid PC Board; the keypad/display board, which is
a two-sided board supporting the DTMF keypad, and a
14-character, dot-matrix display. This board is not field
serviceable. If a fault develops with the keypad, display,
or backlights, the entire board must be replaced. Also,
the top-display model radios contain a small display
board located under the top escutcheon. This provides
2-character, 6-segment, starburst-type display. This
board is not field serviceable. The entire board must be
replaced.
All discrete wiring has been replaced with flexible
circuits: a controls flex, a front cover/display flex, and a
jumper flex. The controls flex interconnects the top con-
trols and the side controls (PTT switch, emergency push
button, telephone-interconnect push button) with the
controller board. The front cover/display flex routes sig-
nals between the controller, the 13-pin universal
connector, the front cover components (speaker and
microphone), and if applicable, the display/keypad
board. The jumper flex routes signals between the
transceiver and the controller board.
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