MFJ MFJ-4402 Instruction Manual

MFJ-4402 Mobile Transceiver Protector Instruction Manual

DISCLAIMER

Information in this manual is designed for user purposes only and is not intended
to supersede information contained in customer regulations, technical
manuals/documents, positional handbooks, or other official publications. The
copy of this manual provided to the customer will not be updated to reflect
current data.

Customers using this manual should report errors or omissions,
recommendations for improvements, or other comments to:

MFJ Enterprises,

300 Industrial Park Road,

Starkville, MS 39759.

Phone: [phone]

FAX: [phone].

Business hours:

M-F 8:00 AM-4:30 PM CST.

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© 2012 MFJ Enterprises, Inc.

MFJ-4402 Mobile Transceiver Protector Instruction Manual

Table of Contents

The MFJ-4402 Mobile Transceiver Protector .................................................... 1

Specifications .................................................................................................... 2

Installation ......................................................................................................... 2

Radio is Already Installed.............................................................................. 3

Radio and Power Lines Not Installed Yet...................................................... 4

Ignition Sense Line Installation.......................................................................... 5

Checkout and Operation................................................................................ 6

Adjustments................................................................................................... 6

Timer Adjustment ...................................................................................... 6

Undervoltage Cutout.................................................................................. 6

Fuse Replacement .................................................................................... 6

Powerpole® Connector Assembly................................................................. 7

Additional Materials That May Be Needed ........................................................ 8

Schematic.......................................................................................................... 9

Troubleshooting................................................................................................. 9

NOTES ............................................................................................................ 11

FULL 12-MONTH WARRANTY....................................................................... 12

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© 2012 MFJ Enterprises, Inc.

MFJ-4402 Mobile Transceiver Protector Instruction Manual

THE MFJ-4402 MOBILE TRANSCEIVER PROTECTOR

This little box helps protect your mobile radio from a number of power related
problems found in vehicles these days

There are times when during starting of the vehicle the battery voltage will sag to
levels that will cause your radio’s controller to act up or corrupt the internal
memory. Some of these symptoms include the radio not powering up correctly,
memory channels lost, and service and setup memory (hidden menus) being
corrupted. Even with the power switch off some of the circuits still have power on
them. The MFJ-4402 has a delay timer circuit controlled from the ignition sense
line insuring your radio does not turn on till your vehicle has started and the
voltage has reached normal levels. This is done by disconnecting the power till
the time out period is completed.

Another issue is operating the radio while the engine is off. At some point the
battery voltage will drop to the point that the radio may not operate correctly such
as distorted audio, frequency shifting with modulation, or even the voltage
dropping to the point that the vehicle will not start. The MFJ-4402 has a circuit to
cut the radio off before the voltage gets down too low for proper operation.

A third issue that occasionally happens is leakage currents in the portions of the
radio that do not get disconnected when the power is turned off rise to levels that
can discharge batteries, especially batteries that are near the end of their life.
The MFJ-4402 disconnects the power to the radio completely from the positive
line to the battery insuring that a radio with high current leakage will not be the
cause of a dead battery.

A fourth issue is a problem with electrical surges. The regulator in the alternator
can go bad causing excessive voltages, sudden changes in loads causing
momentary overshoots of the alternator voltage and jumping off other cars
causing voltage spikes, or even worse a truck with a 24V electrical system trying
to jump off your car. The internal Transient Surge Protector and the fuse make a
protective circuit to catch momentary spikes and blowing the fuse on extended
voltage spikes. The protector will also blow the fuse of the voltage is reversed on
the battery power leads.

Connections between the MFJ-4402 and the vehicle and the radio are made
through Anderson Powerpole® connectors for the high current lines and a quick
disconnect connector for the ignition sense line. A 30A (max) fuse is used to
protect for over current and reverse voltages.

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© 2012 MFJ Enterprises, Inc.

MFJ-4402 Mobile Transceiver Protector Instruction Manual

SPECIFICATIONS

Time Delay 2 to 6.5 sec
set to 4 sec

Low Voltage Dropout 10.25 to 12.4 volts set to 10.8V

Pickup at 10.3 to 12.42 volts

Surge Clamping Voltage 21.2V

Max Radio Current 30A

Ignition Sense Current 120mA

INSTALLATION

Plan the installation out before actually cutting wire or drilling holes. Make sure
you have the tools needed to complete the job and the additional hardware to
properly wire to the car before starting the job. A little planning will save hours
running down to the auto parts or electronics store for forgotten connectors or
parts.

Install the MFJ-4402 in a convenient out of the way place that is not exposed to
outside conditions. The MFJ-4402 is not waterproof or made for exterior use.

Do not use on positive ground vehicles. The MFJ-4402 is designed for negative
ground 12V electrical systems only.

WHEN WORKING AROUND THE BATTERY IT IS RECOMMENDED TO
DISCONNECT THE BATTERY TERMINALS TO REDUCE THE
CHANCE OF A SHORT CIRCUIT. A SHORT CIRCUIT CAN CAUSE
THE BATTERY TO EXPLODE.

Note: The wiring requires connections to the battery and an accessory
connection in the fuse box. If you are not comfortable in making these
connections take your vehicle to a qualified auto electric technician or
someone experienced in mobile equipment installation.

The RED terminals and wires are always connected to the POSITIVE
connections and the BLACK terminals and connections are always connected to
the NEGATIVE or GROUND connections.

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© 2012 MFJ Enterprises, Inc.