MFJ Enterprises MFJ-422B User manual

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MFJ-422B/422B-X INSTRUCTIONS
INTRODUCTION
Thank you for your purchase of the MFJ-422B/422B-X Electronic Keyer. The MFJ-422B/422B-X is
designed to mount on the BENCHER -paddle resulting in a compact, one-piece Keyer/Paddle
combination. The improved Curtis 8044 ABM Keyer IC is used in the MFJ-422B/422B-X to make
perfect code transmission easy and pleasant. Controls are located for easy access while operating.
CONTROLS
1. VOLUME: Adjust the volume of the sidetone from the internal speaker. Functions as the power
ON/OFF switch for the MFJ-422B/422B-X.
2. SPEED: Varies the sending speed from 8 to 50 WPM.
3. AUTO/SEMI-AUTO: AUTO-Normal operating position. Dots and dashes of the correct length are
generated automatically.
SEMI-AUTO:-Dots are generated automatically. Dashes are manually made. (NOTE: In this
position, when the dash paddle is held your transmitter is continuously for tuning.)
4. TONE: Sets the pitch of the sidetones. This control is recessed inside the cabinet between the
VOLUME and SPEED controls. A small flat head screwdriver is needed for adjustment.
5. WEIGHT: Adjusts dot and dash lengths. When turned fully counter-clockwise, dot-dash-space
ratio is a perfect 1:3:1. This control is located on the rear of the cabinet and is also recessed. A
small flat head screwdriver is necessary for adjustment. (NOTE: The weight control is factory
set for a 1:3:1 ratio.)
INSTALLATION
FOR MFJ-422B (KEYER WITH PADDLE)
If you purchased the MFJ-422B (Keyer with Paddle), the keyer will come factory installed on the
paddle and the only connections necessary will be to your transmitter and power supply if used.
If battery operation is desired, remove the rubber foot on the bottom rear of the paddle and
screw holding the plastic wire clamp from the bottom center of the paddle. The keyer will now
slide off the paddle base toward the rear. Install a 9V transistor battery in the battery snap and slip
the battery into the holder. Reverse the above procedure to re-install the keyer onto the paddle.
Feed the connecting cable through the slot on the bottom of the paddle and is clamped securely
with the cable clamp. (NOTE: Long-life Alkaline type batteries are recommended for longest
uninterrupted operation.)

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FOR MFJ-422B-X (KEYER WITHOUT PADDLE)
If you purchased the MFJ-422B-X (Keyer without Paddle) for connection to your own BENCHER -
paddle, follow the procedure below for proper connection.
1. Remove the rubber foot from the bottom rear of your BENCHER -paddle.
2. Remove the plastic cable clamp from the bottom center of the paddle.
3. Solder the shield on the cable from the MFJ-422B-X to the solder lug located between the rear
rubber foot and the cable clamp on the bottom of the paddle.
4. Solder the red wire in the cable from the MFJ-422B-X to the solder lug on the dot post of the
paddle and the white wire to the solder lug on the dash post.
5. If battery operation is desired, install a 9 V transistor battery in the battery snap in the MFJ-
422B-X and slip the battery into the battery holder. (NOTE: Long-life Alkaline type batteries are
recommended for the longest uninterrupted operation.)
6. Replace the screw holding the rear rubber foot on the paddle with the 4-40 × 3/8" screw
supplied with the MFJ-422B-X.
7. The MFJ-422B-X can now be slid onto the BENCHER -paddle from the rear. Feed the cable
through the slot in the bottom right rear of the box. Secure the box to the paddle by
remounting the rear rubber foot through the box to the paddle base. Fold the cable up neatly
and secure with the plastic cable clamp on the bottom of your BENCHER -paddle.
TRANSMITTER CONNECTION
(MFJ-422B/422B-X)
1. Provision is made for powering the MFJ-422B/422B-X with external 5-9V DC supply. A submini-
ture POWER jack is located on the rear of the MFJ-422B/422B-X for this purpose. An optional
AC adapter is available from the MFJ Enterprises, Inc. When a plug is inserted into the POWER
jack, the battery is automatically disconnected. Use an adapter with a 2.5 mm phone plug with
the tip being positive.
2. Connect a shielded cable from the KEYING OUTPUT of the MFJ-422B/422B-X to your trans-
mitter. Consult the instructions for your transmitter to determine whether to use the "Direct" or
"Grid block" output jack. (NOTE: If in doubt as to which jack to use, try both jacks. If the
transmitter keys continuously when the cable is plugged into one jack, use the other one.)

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OPERATION
After proper connection of the MFJ-422B/422B-X you are ready for operation. Rotate the
VOLUME control clockwise to turn power on as indicated by the LED light. Start sending with the
paddle and adjust the VOLUME, SPEED, TONE, and WEIGHT controls to your preference. (NOTE: If
a steady tone at high speed occurs, reduce the WEIGHT or the SPEED by turning the respective
control counter-clockwise.)
The dot and dash memory feature of the Curtis 8044 ABM-IC makes sending easier. This feature
allows keying a dot before completion of a dash or vice versa. This feature can be checked by
setting the keyer to the lowest speed and tapping first the dash paddle and then the dot paddle
before of the dash. The dash memory can be checked in a similar manner. The dot insertion
feature allows you to tap the dot paddle while holding in the dash paddle. A dot will be insert
automatically. The dash insertion feature allows you to insert a dash while holding in the dot
paddle. With both paddles squeezed, the IAMBIC operation feature allows sending of alternate
dots and dashes. First paddle contact determine whether a dot or a dash occurs first.
Reprint: DC7XJ – XI.2020

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