ELECRAFT K1 Owner's Manual download pdf (Page 8)

From March 2001 QST © ARRL

the color of each wire and where it went

in the original configuration. This is es-

pecially important should you decide to

assemble and install the kit over several

sessions—don’t rely on memory alone!

A couple of warnings are in order here.

The wires originally used within these

control boxes are typically solid conduc-

tor and the insulation on them has a low

melting point. If you linger too long with

the soldering iron you’ll melt the insula-

tion off the wires. Most of the wires in

my control box were long enough to snip

them off at their connection points and

strip off a little more insulation for reat-

tachment.

There is a common modification that

has been made to many of these control

boxes over the years that keeps the brake

off for a few seconds after you let go of

the

BRAKE RELEASE lever (see Figure

7). Rotor-EZ takes care of all brake de-

lay operations, so if your box has had this

change made, you’ll want to begin by re-

versing this—and any other—user-in-

stalled modifications. The instructions

naturally assume that you are installing

Rotor-EZ in an unmodified unit.

I proceeded carefully through the pro-

cess of interfacing the new brain to the

remaining control box circuitry. There are

quite a few wires involved. Take your

time and pay close attention to properly

dressing the leads. The completed instal-

lation is shown in Figure 8.

I then double-checked all my connec-

tions and applied power. Success! All of

the smoke stayed in the components and

the rotary

CALIBRATE

control and switches

all appeared to behave properly. I followed

the calibration instructions and had the

rotator system back in operation within

four hours of initially opening the case.

The Instructions and User Manual

I found the instructions to be clear and

straightforward, but there are no draw-

ings—text only. When I asked Idiom

Press about this, they told me that they

have identified (among unmodified con-

trollers) five different meter movements

and at least three significantly different

component layouts. There are also minor

variations among these. Early boxes em-

ployed separate components where later

boxes used printed circuit boards. Even

then, there are at least two different ver-

sions of PC board models.

Since it would take a significant num-

ber of drawings or photographs to cover

all of the possible variations, the instruc-

tions rely completely on text descrip-

tions—and they do a very good job. I was

able to complete the installation phase

successfully by carefully following each

step. Providing a table for the builder to

jot down notes detailing where the origi-

nal wires are routed would be a helpful

addition, but scrap paper will suffice. On

a scale of 0 (totally confounding) to 10

(Heathkit-like), I would rate these in-

structions a 7.

Opportunities for Improvement

The component labeling on Rotor-EZ’s

PC board could have been clearer—some

of the silk-screened text designators are

obscured or overlay a solder pad. Also, the

Figure 4—The Rotor-EZ with RS-232 kit as delivered. The 3

/8 × 3

/16-inch double-

sided circuit board is solder masked and silk screened with component outlines

and parts numbers. Everything you’ll need—including hookup wire and wire ties—

is included.

Figure 5—The assembled Rotor-EZ circuit board ready for

installation in the rotator control box. The vacant 28-pin socket

in the lower right hand corner of the board is for the PIC16C73

microprocessor.

Figure 6—My Tailtwister control box awaits “brain surgery.” The

Rotor-EZ circuit board will be replacing the original one that’s

mounted on the meter studs (located just to the right of the

large transformer in this photograph).

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ELECRAFT K1 Owner's Manual Page 8

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