MFJ MFJ-401D User Manual
MFJ-401D Instruction Manual Econo Keyer II
Introduction
The MFJ-401D Econo Keyer II is a microprocessor controlled keyer that provides
iambic key operation and dot-and-dash memory to make sending perfect code
easier. It has tunable code speed, code weight, and sidetone frequency; it
supports both direct and grid-block keying outputs. You also get to choose
between Iambic Type "A" and Type "B" keying.
Control Functions
1. The Power button turns the unit ON and OFF. The power is ON when the
button is locked in the "in" position and OFF in the "out" position.
2. The Semi-Auto/Auto button allows semi-automatic "bug" and manual
operations. The keyer generates dots automatically when a squeeze or
single lever key is used. Dashes are manually made. The keyer is
completely manual when a straight ke y is used. Semi-Auto is active when
the switch is in the "in" position and Auto when in the "out" position.
3. The Speed control varies the code speed. The speed range is configured
with an internal jumper (JMP9) for 5 to 65 WPM or 10 to 40 WPM. Turn t he
control clockwise to increase speed and counter-clockwise to decrease
speed. The unit is factory set to 5 to 65 WPM. To make the speed
adjustment less sensitive, change the speed range to the narrower range of
10 to 40 WPM. To change the speed range the power must be off, then
remove the cover by removing the two screws (one on each side) that secure
it. Locate jumper JMP9 and set it to the "H" position.
Note: Power must be off when changing the jumper settings.
4. The Weight control varies the code weight from approximately 25% to 75%,
with the standard dot defined as 50% weight. The standard dot-dash-space
ratio is 1:3:1 (trimpot at mid -range). Turn the control clockwise to increase
dot and dash lengths and counter-clockwise to decrease dot and dash
lengths. This control is located internally. When looking at the unit's front
panel, it is accessible through the small hole on the left side, closest to the
rear and may be adjusted by inserting a small, flat-headed screwdriver.
5. The Tone contro l sets the desired sidetone pitch from approximately 300 to
1200 Hz. Turn the control clockwise to raise the pitch and counter -clockwise
to lower the pitch. This control is located internally. When looking at the
unit's front panel, it is accessible through the small hole on the left side,
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MFJ-401D Instruction Manual Econo Keyer II
closest to the front and may be adjusted by inserting a small, flat-headed
screwdriver.
6. The Volume control adjusts the sidetone level of the internal speaker. Turn
the control clockwise to increase the volume and counter-clockwise to
decrease the volume.
7. The Direct/Grid-Block Output keying circuit allows keying of grid-block
and solid state transmitters. The MFJ-401D can only key one type of
transmitter at a time. This is an internal jumper selected option. The unit is
factory set to direct keying. To change to grid -block keying the power must
be off, then remove the cover by removing the two screws (one on each
side) that secure it. Locate JMP1 and JMP2. JMP2 is directly behind the
RCA jack and JMP1 is approximately one inch in front of JMP2. Set both
jumpers JMP1 and JMP2 to the "G" position. To key a solid state
transmitter, set both jumpers to the "D" position.
Note: Power must be off when changing the jumper settings.
8. The Iambic Type A/B mode is also set inside the unit with a jumper. The
unit is factory set for Type "A" Iambic. If you prefer Type "B" Iambic,
remove the cover by removing the two screws (one on each side) that secure
it. Locate jumper JMP3 and set it to the "B" position. For Type "A" Iambic,
set the jumper to the "A" position.
Note: Power must be off when changing the jumper settings.
When a squeeze is released during an element (dot or dash), type "B" adds
the opposite element. Type "A" just finishes the element in progress and
does not produce a following alternate element. For example, in Type "A"
Iambic, a squeeze release during the "dah" in the letter A will produce "didah" (A). In Type "B" Iambic, a squeeze release during the "dah" in the
letter A will produce "di -dah-dit" (R).
Installation
1. A 9-volt battery (not included) may be installed. Remove the cover by
removing the two screws (one on each side) that secure it.. A battery
holder, located inside the enclosure, is provided for installing a 9-volt
battery.
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MFJ-401D Instruction Manual Econo Keyer II
2. A 12 Vdc power supply may also be used to power the MFJ-401D. A 2.1mm
coaxial plug with a positive center and a negative sleeve should be used to
power this unit. The MFJ-1312B, an optional 12 volts adapter, is available
from MFJ Enterprises, Inc. The battery is automatically disconnected when
external power is used.
3. A squeeze or single lever key can be used. Squeeze key allows Iambic
operation. A 1/4-inch stereo phono plug and a two-conductor shielded
cable should be used. If separate shielded cables are used, the two shields
should be tied together and connected to ground. The dot wire should be
connected to the tip of the plug and the dash wire to the ring. The MFJ401D becomes a manual keyer when a straight key is used. The unit will
safely key your transmitter and eliminate the shock hazard of high voltage
being present on the straight key.
Note: To use a straight key, first switch the keyer to the Semi -Auto mode
(button in). Again a 1/4-inch stereo phono plug should be used
because a mono plug will not work on a straight key in Semi -Auto
mode. Connect one wire to the ring of the plug and another wire to
ground. The tip of the plug should not used.
4. Output keying circuit allows keying of grid-block and solid state
transmitters. Re member this is internally jumper selected (refer to page 2).
The keying output connection is made with a RCA phono plug.
Note: Consult the transmitter's instruction manual to determine which
output to use. When in doubt, try both jumper positions. The
transmitter will key continuously when the jumpers are connected to
the wrong positions.
Keyer Operation
1. A 9-volt battery or an optional dc adapter may be used to supply power to
the keyer.
2. The key paddle should be connected to the Key jack on the rear panel of the
unit. A dual paddle squeeze key or a single lever key can be used.
3. Next, the keyer should be turned on with the Power switch.
4. The Semi-Auto/Auto switch should be in the "out" position for automatic
operation.
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