MFJ MFJ-393Y, MFJ-393K, MFJ-393I User Manual

12 MONTH LIMITED WARRANTY

MFJ Enterprises, Inc. Warrants to the original owner of this product, if manufactured by MFJ
Enterprises, Inc. and purchased from an authorized dealer or directly from MFJ Enterprises,
Inc. to be free from defects in material and workmanship for a period of 12 months from date
of purchase provided the following terms of this warranty are satisfied.

1. The purchaser must retain the dated proof-of-purchase (bill of sale, canceled check, credit card or
money order receipt, etc.) describing the product to establish the validity of the warranty claim and
submit the original or machine reproduction of such proof-of-purchase to MFJ Enterprises, Inc. at
the time of warranty service. MFJ Enterprises, Inc. shall have the discretion to deny wa rranty
without dated proof-of-purchase. Any evidence of alteration, erasure, or forgery shall be cause to
void any and all warranty terms immediately.

2. MFJ Enterprises, Inc. agrees to repair or replace at MFJ’s option without charge to the original
owner any defective product under warranty, provided the product is returned postage prepaid to
MFJ Enterprises, Inc. with a personal check, cashiers check, or money order for $7.00 covering
postage and handling.

3. MFJ Enterprises, Inc. will supply replacement parts free of charge for any MFJ product under
warranty upon request. A dated proof-of-purchase and a $5.00 personal check, cashiers check, or
money order must be provided to cover postage and handling.

4. This warranty is NOT void for owners who attempt to repair defective units. Technical consultation
is available by calling [phone].

5. This warranty does not apply to kits sold by or manufactured by MFJ Enterprises, Inc.

6. Wired and tested PC board products are covered by this warranty provided only the wired and tested
PC board product is returned. Wired and tested PC boards installed in the owner’s cabinet or
connected to switches, jacks, or cables, etc. sent to MFJ Enterprises, Inc. will be returned at the
owner’s expense unrepaired.

7. Under no circum stances is MFJ Enterprises, Inc. liable for consequential damages to person or
property by the use of any MFJ products.

8. Out-of-warranty Service: MFJ Enterprises, Inc. will repair any out -of-warranty product provided the
unit is shipped prepaid. All repaired units will be shipped COD to the owner. Repair charges will
be added to the COD fee unless other arrangements are made.

9. This warranty is given in lieu of any other warranty expressed or implied.

10. MFJ Enterprises, Inc. reserves the right to make changes or improvements in design or manufacture
without incurring any obligation to install such changes upon any of the products previously
manufactured.

11. All MFJ products to be serviced in -warranty or out-of-warranty should be addressed to MFJ
Enterprises, Inc., 300 Industrial Park Road, Starkville, Mississippi 39759, USA and must be
accompanied by a letter describing the problem in detail along with a copy of your dated proof-of­purchase.

12. This warranty gives you specific rights, and you may also have other rights, which vary from state to
state.

MFJ-393

Deluxe Headset Microphone

Thank you for purchasing the MFJ-393 Deluxe Headset Microphone. The MFJ­393 microphone has an electret condenser microphone element. This microphone
element requires a DC power source from 1V to 9V (3V standard operating voltage)
in order to function properly. Some transceivers have dc power available on one of
the microphone pins and this can be used to power the microphone.

You may purchase an optional adaptor cable from MFJ or you can make one of
your own from the information provided in this manual. The MFJ microphone
adaptor cable available assumes that your transceiver has a pin out configuration that
matches one that is shown in the chart in this manual. If your transceiver does not
have this pin out configuration you cannot use the MFJ microphone adaptor cable
and you must make one of your own to match your transceiver microphone pin-out.
Note that if your transceiver does not have a suitable DC power source present on the
microphone connector, you must supply an external DC voltage from 1V to 9V (3V
standard operating voltage) to the microphone element. The MFJ-393 microphone
will not function without a DC supply voltage to the microphone element.

Caution: Do not apply dc directly to the microphone element. This may
damage the element. A resistor must be added in series with the dc supply
(suggested value 3.3kΩto 10kΩ).

The white 3.5mm stereo plug for the microphone is wired as follows:

The black 3.5mm stereo plug for the headset audio is wired as follows:

Audio Output Features:

• Oversize dual ear cushions

• 40mm ferrite drive units

• 32Ω Impedance

• 116 dB at 1 KHz Sensitivity

• 20-20,000 Hz frequency response

• Handles 100 mw maximum power

• In-line volume control

• 3.5mm stereo plug for audio (Black)

Microphone Input Features:

• 9.7mm diameter electret condenser microphone element

• Omni -directional

• Low Impedance

• -62 dB sensitivity

• 30-16,000 Hz frequency response

• 3 VDC standard operating voltage

• 3.5mm stereo plug for microphone (White)

Operation with MFJ adaptor cable:

• The black 3.5mm stereo plug is the headphone plug. Plug this into the “Phone”

jack on your transceiver. A 3.5mm stereo to ¼” mono adaptor might be
required depending on your transceiver.

• Plug the white 3.5mm stereo plug into 3.5mm jack on the MFJ microphone

adaptor cable.

• Plug the microphone adaptor cable into your transceiver.

• The ¼” jack on the MFJ microphone adaptor cable is for an external foot switch

or thumb switch.

• If you do not connect an external PTT device to the MFJ microphone adaptor

cable you must operate your transceiver in VOX mode.

The MFJ microphone adaptor cable series are designed for the following transceivers
with these microphone plug configurations. Remember if your transceiver does not
have this pin out configuration you cannot use the MFJ microphone adaptor cable.

Front View

MFJ Model No. Transceiver 8-Pin Round Microphone Plug

MFJ-5393I ICOM

1 – MIC (Normally has voltage)
2 – +8VDC
5 – PTT
6 – GND (PTT)
7 – GND (MIC)

MFJ-5393K Kenwood

1 – MIC
2 – PTT
5 – +8VDC
7 – GND (MIC)
8 – GND (PTT)

MFJ-5393Y Yaesu*

5 – GND (PTT)
6 – PTT
7 – GND (MIC)
8 – MIC

* Most Yaesu transceivers do not have voltage to power the microphone element. A 9V battery must be
installed in the battery snap to activate the microphone.