Lectrosonics Pro 4 Mini User Manual

PRO 4 MINI

MULTI CHANNEL WIRELESS SYSTEM

WITH CDM4 DISTRIBUTION MODULE

OPERATING INSTRUCTIONS

and trouble-shooting guide

LECTROSONICS, INC.

Rio Rancho, NM

INTRODUCTION

The PRO 4 mini system is a high quality wireless microphone system designed primarily for motion picture and
television production - both in the studio and in the field. The design features included are the direct result of
suggestions garnered during many conversations with industry engineers, cameramen, and audio producers.
These suggestions, together with meticulous attention to design and construction details, have resulted in a system
that offers portability, versatility, and "bullet-proof" reliability of operation.

The PRO 4 mini system consists of a CDM4 RF/power distribution module and a rechargeable battery pack
installed in a compact machined aluminum housing. The PRO 4 mini system is available with up to four CR185
wireless receivers and companion transmitters, or by itself to combine existing CR185 receivers. The system
comes in a padded, reinforced naugahyde carrying case. Zippered front and rear panels provide easy access to
controls and connectors.

Problems such as interaction of receivers, intermodulation and desensitization, etc. have been eliminated through
creative engineering and superior design. The integral CDM4 distribution modules provides convenience of
operation from a single antenna and power supply without degrading the performance of the CR185 receivers. In
fact, the additional RF filtering in the CDM4 module actually improves the already outstanding selectivity of the
CR185 receivers.

The PRO 4 mini makes portable multi-channel wireless simple and trouble-free.

TABLE OF CONTENTS

INTRODUCTION .......................................... 2

GENERAL TECHNICAL DESCRIPTION .......................... 2

FRONT PANEL DESCRIPTION ................................ 3

REAR PANEL DESCRIPTION ................................. 4

INSTALLATION ........................................... 5

OPERATING INSTRUCTIONS ................................. 5

TROUBLESHOOTING ....................................... 6

SPECIFICATIONS ......................................... 7

SERVICE AND REPAIR ..................................... 8

RETURNING UNITS FOR REPAIR ............................. 8

WARRANTY ....................................... Back cover

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GENERAL TECHNICAL DESCRIPTION

The PRO 4 mini consists of two sub-systems; the housing which contains the gel-cell power supply and the
modules, and the CDM4 RF/power distribution module.

The housing is built of machined aluminum and covered with a vinyl carrying case. The handle is bolted directly to
the top aluminum panel of the case for security. The 6V, 4.8 Ah Panasonic LCR-456-P lead-acid gel-cell batteries
are connected in series to provide 12 Vdc power to all the modules installed into the system. These batteries were
selected for their recharge characteristics and reliability under extreme conditions.

The CDM4 RF/power distribution module is the heart of the PRO 4 mini system. Helical resonators in the front end
of the RF section attenuate out-of-band RF signals preventing intermodulation and front end overload. Following
the resonators is a low noise, low gain RF amplifier designed to evenly compensate for splitter losses in the stage
that follows. A precision splitter/isolator divides the RF signal into four isolated signals preventing spurious RF
coupling between receivers. The splitter/isolator is termination independent which prevents mismatched or
disconnected RF outputs from affecting the other receivers.

Power can be supplied to the CDM4 module from four possible sources. The primary source is the gel-cell battery
pack built into the bottom of the housing. Power may also be provided through an external DC power source of 12
to 20 Vdc of either polarity. When an external source is connected, an internal relay automatically disconnects the
internal battery pack. If that DC source fails or is disconnected, the system automatically reverts to the internal
batteries. AC power can be provided through the CH-50 charger included with the unit. While operating in the AC
mode, the internal batteries are also recharged. The individual receivers and the CDM4 module can also be
operated from internal 9V alkaline batteries housed inside each unit’s battery compartment. In this mode of
operation, all receivers and the CDM4 have to be manually switched for "internal" power. All power circuits are
protected by internal auto-reset fuses in the CDM4. Should the power to one receiver fail, the others will continue
to operate.

Figure 1 - PRO 4 mini Block Diagram

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