MFJ MFJ-4175 User Manual

Model MFJ-4175

VERSION 1A

INSTRUCTION MANUAL

CAUTION: Read All Instructions Before Operating Equipment

MFJ ENTERPRISES, INC.

300 Industrial Park Road

Starkville, MS 39759 USA

Tel: [phone] Fax: [phone]

COPYRIGHT 2006 MFJ ENTERPRISES, INC.

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MFJ-4175 Instruction Manual Switching Power Supply

Thank you for purchasing the MFJ-4175 Switching Power Supply.
The MFJ-4175 Switching Power Supply is a perfect match to power any Solid State Amplifier.
The MFJ-4175 is designed to supply 75 amps continuously at 13.8Vdc. The MFJ-4175 is
protected by multiple protection features for a long, trouble-free life.

MFJ-4175 features

1. Reverse Battery Polarity Protection

2. Brown-out Input Protection

3. Over-Current Protection: Cycle-by-cycle peak limiting as well as rated current limiting
to maximize the life of the power supply.

4. Over-Temperature Protection: Proportional Fan Control – fan speed is directly
proportional to the power supply’s internal ambient temperature. This enables the fan to
turn on and off very slowly, minimizing unwanted fan-starting noise.

5. Output Voltage Boost: Steps up the voltage from 13.8Vdc to 14.6Vdc.

Specifications:

Output

Voltage

13.8 Vdc 75 amps

Installation

Locate the MFJ-4175 in a location that provides sufficient air space to allow unrestricted airflow
in and around the unit. MFJ-4175 should not be located next to your radio.

MFJ-4175 is supplied with an AC line cord with a NEMA 5-15P Plug. Make sure that the AC
outlet to be used is capable of supplying 20 amps at 110 Vac with a 3-wire grounded NEMA 5­15P compatible socket. The MFJ-4175 draws 18 amps at the rated output.

Connect the amplifier or load to the output terminal block of the MFJ-4175. Unscrew the set
screws on the top of the terminal block with a flat blade screwdriver. To insure that the power
cables make secure contact with the MFJ-4175 output terminal, prepare the cable end by twisting
stripped end tightly. Bond the end with solder. Connect the Positive cable to the (+) terminal
hole. Connect the Negative cable to the (NEG) terminal hole. Screw the set screw tightly to
secure the cable in the terminal block. Connect the “Chassis Bonding Lug” on the MFJ-4175 to
the amplifier chassis ground or other grounding source.

Main power ON/OFF switch is located on top of the MFJ-4175.

Caution: The MFJ-4175 is a 75 amps power supply, if the output connection is not installed
properly, the terminal block will overhead and be destroyed in time.

Max

Output

Current dc

Continuous

Max Output

Power Watt /

VA

1260 Watts /

1944 VA

Input

Voltage

108 – 132

Volts AC

Input

Voltage

Current

18 amp AC 40-70 Hz

Line

Frequency

2