ELECRAFT K3 User manual

ELECRAFTK3
HIGH-PERFORMANCE 160 – 6 METER
TRANSCEIVER
K3 KIT ASSEMBLY MANUAL
Rev D, December 26, 2007
Copyright © 2007, Elecraft, Inc.
All Rights Reserved

i
Contents
Introduction...................................................... 1
Customer Service and Support............................1
Technical Assistance.......................................1
Preventing Electrostatic Discharge Damage ... 3
How ESD Damage Occurs..................................3
Preventing ESD Damage.....................................3
Preparing for Assembly................................... 4
Overview of the Kit.............................................4
Tools and Test Equipment Required...................6
Unpacking and Inventory....................................7
Screws.............................................................7
Standoffs .........................................................8
Lock Washers..................................................8
Assembly ......................................................... 9
RF Board and Chassis.......................................10
RF Board Description ...................................10
RF Board and Chassis Assembly Procedure.10
KANT3 or KAT3, Right Side and Rear Panels 18
KANT3 or KAT3 Description.......................18
KANT3 or KAT3, Right Side and Rear Panel
Installation Procedure....................................18
KIO3 Interface ..................................................23
KIO3 Description..........................................23
KIO3 Interface Installation Procedure ..........23
Front Panel and DSP.........................................26
Front Panel and DSP Description..................26
Front Panel Assembly Procedure..................26
Resistance Checks.........................................39
Initial Power On Check.................................40
KREF3 Reference Oscillator.............................40
KREF3 Description.......................................40
KREF3 Installation Procedure ......................40
KSYN3 Synthesizer ..........................................42
KSYN3 Description......................................42
KSYN3 Installation Procedure......................42
Loudspeaker......................................................44
Loudspeaker Description ..............................44
Loudspeaker Installation Procedure..............44
KPA3 Shield......................................................47
KPA3 Shield Description..............................47
KPA3 Shield Installation Procedure .............47
Bottom Cover....................................................49
Bottom Cover Description ............................49
Bottom Cover Hardware Installation ............49
KNB3 Noise Blanker ........................................51
KNB3 Noise Blanker Description.................51
KNB3 Installation .........................................51
Battery BT1.......................................................52
Battery BT1 Description ...............................52
Battery BT1 Installation Procedure ..............52
KBPF3 General Coverage Receive Option ......53
KBPF3 Description....................................... 53
KBPF3 Installation .......................................53
Power Amplifier Jumper Block........................54
Finishing the Enclosure .................................... 54
Fan Opening Cover....................................... 54
Bottom Covers.............................................. 55
Top Cover.....................................................56
Test and Calibration.......................................57
Initial Power Checks......................................... 57
Synthesizer Calibration.....................................58
Filter Setup ....................................................... 58
Reference Oscillator Calibration ......................58
TX Gain Calibration.........................................58
Option Modules................................................58
Enable Modules................................................58
KPA3 100-Watt Amplifier Installation ............58
Other Calibration Procedures ...........................59
Wattmeter Calibration (Optional)..................... 59
S-Meter Calibration (Optional).........................59
Appendix A, Illustrated Parts List................................ A1

1
Introduction
This manual will guide you through assembly of your Elecraft K3 transceiver. We’re confident that you’ll find
the K3 easy to build, even if you’ve had no prior kit-building experience.
Every modern transceiver is complex, and the K3 is no exception. The kit includes nearly 300 individual
components, including over a dozen PC boards and a multi-element modular chassis. But the K3's unique design
eliminates some of the tedious aspects of construction, enabling you to complete assembly in far less time than
previous high-performance transceiver kits. Also, virtually all of the alignment is handled in firmware using the
K3's built-in test capabilities.
If you should you have difficulty, you'll have our full support via phone and e-mail. In addition, we hope you'll
join our growing and enthusiastic community of owner/builders via the Elecraft reflector.
Further information about the Elecraft K3, including specifications, installation, and operation instructions, can
be found in the Owner’s Manual.
Customer Service and Support
Technical Assistance
You can send e-mail to [email protected] and we will respond quickly - typically the same day Monday
through Friday. Telephone assistance is available from 9 A.M. to 5 P.M. Pacific time (weekdays only) at 831-
662-8345. Please use e-mail rather than calling when possible since this gives us a written record of the details
of your problem and allows us to handle a larger number of requests each day.
Repair / Alignment Service (We want to make sure everyone succeeds!)
If necessary, you may return your Elecraft product to us for repair or alignment. (Note: We offer unlimited email
and phone support to get your kit running, so please try that route first as we can usually help you find the
problem quickly.)
IMPORTANT: You must contact Elecraft before mailing your product to obtain authorization for the
return, what address to ship it to and current information on repair fees and turn around times. (Frequently we
can determine the cause of your problem and save you the trouble of shipping it back to us.) Our repair location
is different from our factory location in Aptos. We will give you the address to ship your kit to at the time of
repair authorization. Packages shipped to Aptos without authorization will incur an additional shipping charge
for reshipment from Aptos to our repair depot.

2
Elecraft 1-Year Limited Warranty
This warranty is effective as of the date of first consumer purchase. It covers both our kits and
fully assembled products. For kits, before requesting warranty service, you should fully complete
the assembly, carefully following all instructions in the manual.
What is covered: During the first year after date of purchase (or if shipped from factory, date
product is shipped to customer), Elecraft will replace defective or missing parts free of charge
(post-paid). We will also correct any malfunction to kits or assembled units caused by defective
parts and materials. Purchaser pays inbound shipping to us for warranty repair, we pay shipping to
return the repaired equipment to you by UPS ground service or equivalent to the continental USA
and Canada. Alaska, Hawaii and outside U.S. and Canada actual return shipping cost paid by
owner.
What is not covered: This warranty does not cover correction of kit assembly errors. It also does
not cover misalignment; repair of damage caused by misuse, negligence, or builder modifications;
or any performance malfunctions involving non-Elecraft accessory equipment. The use of acid-
core solder, water-soluble flux solder, or any corrosive or conductive flux or solvent will void this
warranty in its entirety. Also not covered is reimbursement for loss of use, inconvenience,
customer assembly or alignment time, or cost of unauthorized service.
Limitation of incidental or consequential damages: This warranty does not extend to non-
Elecraft equipment or components used in conjunction with our products. Any such repair or
replacement is the responsibility of the customer. Elecraft will not be liable for any special,
indirect, incidental or consequential damages, including but not limited to any loss of business or
profits.

3
Preventing Electrostatic Discharge Damage
There is no climate or work location where the components of your K3 are safe from Electrostatic Discharge
(ESD) unless you take specific steps to prevent such damage. Many of the components in your K3 can be
damaged by static discharges of only a few volts: far too little for you to notice. It is those low-voltage but
destructive discharges that easily happen anywhere and under virtually any environmental conditions.
ESD damage may not be apparent at first. The damaged components may not fail completely. Instead, the
damage may result in below-normal performance for an extended period of time before you experience a total
failure.
How ESD Damage Occurs
Whenever an object containing a static charge touches a circuit in your K3, current will rush into the circuit until
the components reach the same voltage as the source of the static charge. If the voltage or current that passes
through a component in your K3 during that brief period exceeds its normal operating specifications, it may be
damaged or destroyed.
Preventing ESD Damage
ESD damage cannot occur if there is no voltage difference between the components in your K3 and any object
that touches them. That is how anti-static packaging works. Anti-static bags allow the static charge to flow over
their surface, so that any part of the bag that touches the components inside are all at the same potential at all
times. Anti-static foam keeps the leads of sensitive components at the same potential.
At your work bench, avoiding a dangerous voltage is achieved most easily by tying everything together and
connecting them to a common mains safety ground. This includes your K3, individual boards or other sensitive
components as well as everything they may touch at the work table.
Inexpensive static dissipating work mats are readily-available that will steadily and safely drain off any charges
built up on parts or circuit boards placed on them. They are supplied with a lead that connects the mat to the
common workbench ground. Also, metal cabinets on test equipment used on the bench should be tied together
and connected to the common ground.
Most importantly, you must have a way of continuously draining off any static charges that occur on your body.
Such charges are easy to create, even while sitting quietly at the work bench. Moving your feet on the floor,
shifting position in your chair or even moving your arms so that clothing rubs against itself can all produce
destructive static charges. You can discharge yourself by touching an unpainted metal ground, but that will last
only until you move in a way that produces a new static charge. The safest technique is to wear a grounded wrist
strap with a series 1-megohm resistor that continuously drains off any charges. Such wrist straps are readily-
available and inexpensive.
WARNING
DO NOT attach a ground directly to yourself without a current-limiting resistor as this poses
a serious shock hazard. A wrist strap must include a 1-megohm resistor to limit the current
flow. If you choose to touch an unpainted, metal ground to discharge yourself, do it only
when you are not touching any live circuits with your other hand or any part of your body.
We strongly recommend you take the following anti-static precautions (listed in order of importance) to avoid
trouble:
xLeave ESD-sensitive parts in their anti-static packaging until you install them. The packaging may be a
special plastic bag or the component’s leads may be inserted in conductive foam. Parts which are

4
especially ESD-sensitive are identified in the parts list and in the assembly procedures.
xWear a conductive wrist strap with a series 1-megohm resistor. If you do not have a wrist strap, touch a
ground briefly before touching any sensitive parts to discharge your body. Do this frequently while you
are working. You can collect a destructive static charge on your body just sitting at the work bench. DO
NOT attach a ground directly to yourself as this poses a serious shock hazard.
xUse a grounded anti-static mat on your work bench.
xIf you choose to use a soldering iron to work on your K3 for any reason, be sure the iron is ESD-safe
with a grounded tip tied to the same common ground used by your mat or wrist strap.
Preparing for Assembly
Overview of the Kit
The kit comprises two major assemblies: the main chassis and the front panel. Figure 1 shows an assembled
K3/10 with its top cover removed.
The main chassis is literally built up around the RF circuit board, which fills the entire bottom of the unit of the
chassis assembly. Panels are mounted around the RF board using Elecraft’s 2D fasteners. These fasteners allow
individual removal of any one panel, if needed, to gain access to the inside of the radio for servicing. Very few
cables or wires are used in the kit. Most of the other boards and optional accessories plug directly into the RF
board or one of the boards mounted on the RF board.
The front panel assembly, including the display and main operator controls, includes the front panel board and
the digital signal processing (DSP) board.
There are many options that you can add to the basic K3/10, such as the 100 watt amplifier module, internal
antenna tuner, second receiver, additional crystal I.F. filters, etc. If you purchased these options with your K3
kit, you will find instructions to install them at proper places in the assembly procedure to make getting your
complete K3 together and operational in the most efficient manner.

5
FRONT PANEL
ASSEMBLY
(INCLUDING
K3 DSP AND
K3 FRONT PANEL
BOARDS)
K3 DSP BOARD
K3 FRONT PANEL
BOARD (HIDDEN)
KREF3
BOARD
KSYN3
BOARD
K3 MIXER
BOARD
KNB3
BOARD CRYSTAL
FILTERS
(OPTIONAL
8-POLE
FILTERS
SHOWN)
KANT3
OR OPTIONAL
KAT3 BOARD
(KAT3 SHOWN)
K3 LPA
BOARD
KIO3
BOARD
KIO3
REMOTE
I/O MODULE
KIO3 AUDIO
I/O MODULE
AND OPTIONAL
KXV3 MODULE
(HIDDEN)
FRONT
PANEL
SHIELD
K3 RF
BOARD
(FILLS
BOTTOM OF
CHASSIS
ASSEMBLY)
K3 CHASSIS
ASSEMBLY
PA JUMPER
BLOCK
Figure 1. Assembled K3/10 (Less Top Cover).

6
Tools and Test Equipment Required
1. #0 and #1 size Phillips screwdrivers. To avoid damaging screws and nuts, do not use a power
screwdriver. Use the screwdriver that best fits the screw in each step.
2. Soft cloth or other surface to lay cabinet panels on to avoid scratching. A clean static-dissipating mat is
ideal (see below). If using cloth, do not lay circuit boards on it.. See Preventing Electrostatic
Discharge Damage on page 3.
3. Pliers or suitable wrenches for tightening 1/4”, 3/16” and 1/2” nuts. The 1/2” size is used to tighten nuts
on the front panel controls. If available, a deep socket or nut driver is recommended. Pliers or an
ordinary wrench can be used, but requires care to avoid damaging the front panel paint.
4. Long nose pliers.
5. Diagonal cutters.
6. Small rule capable of measuring lengths up to 1” (2.5 cm) with an accuracy of at least 1/16” inch
(1.6 mm).
7. Digital Multimeter (DMM) for resistance checks.
8. RF 50-ohm, 5 W (minimum) dummy load with low VSWR from 160 meters through 6 meters.
9. Power supply 13 VDC nominal (11-16 V) with a cable and Anderson PowerPole®connector. A power
cable kit is provided with your K3 if you do not have a suitable cable with the required Anderson
PowerPole connector. The power supply must be capable of providing at least 3 Amperes for a K3/10
and 20 Amperes for a K3/100. (See Specifications in your Owner’s manual for more information on
power supply recommendations).
The following tools are strongly recommended:
1. ESD wrist strap.
2. Static dissipating work mat.
Optional Equipment:
1. RF Power Meter with accurate readout from 1 mW to 5 watts, minimum.
2. Signal generator with calibrated 50 uV output at 20 or 40 meters.
In addition, two Allen wrenches, 5/64” (2mm) and .050”, are supplied with your kit.

7
Unpacking and Inventory
CAUTION
Do not handle the circuit boards without anti-static protection! Doing so may damage
sensitive components. See Preventing Electrostatic Discharge Damage on page 3 for important
information before proceeding.
Before starting construction, do a complete inventory, comparing the parts in your kit with the parts list in
Appendix A, to familiarize yourself with all of the parts and to ensure the kit is complete. Note that you may
find some extra screws, nuts and washers. A few extras of the more easily lost parts are included on purpose.
All dimensions given in the assembly procedure are provided in both US customary (often called English) and
metric measurements. The native dimensions of the parts are in US Customary units. Approximate metric
equivalents are given to assist those more familiar with that system to identify the correct parts.
Screws
A number of different types and sizes of screws and washers are used in the assembly. It is very important that
you use the screw specified in each location or your finished K3 may not fit together properly. In some places,
using the wrong size screw may damage components. The following various screw types and sizes specified in
the text are shown in Figure 2. Images are shown for comparing relative sizes. They are not to scale. The length
of the screws called for in the text are measured as shown.
2-56 5/32" (4.0 mm) BLACK PAN HEAD
2-56 1/4" (6.4 mm) BLACK PAN HEAD
4-40 3/16" (4.8 mm) BLACK PAN HEAD
4-40 3/16" (4.8 mm)BLACK FLAT HEAD
4-40 1/4" (6.4 mm) BLACK PAN HEAD
4-40 3/8" (9.5 mm) BLACK PAN HEAD
4-40 1/4" (6.4 mm) ZINC PAN HEAD
4-40 3/8" (9.5 mm) BLACK FLAT HEAD
4-40 7/16" (11 mm) ZINC PAN HEAD
4-40 1/2" (13 mm) BLACK FLAT HEAD
6-32 1/2" (13 mm) BLACK PAN HEAD
SCREW AS IDENTIFIED IN TEXT RELATIVE SIZE
(NOT TO SCALE) MEASURING SCREW
LENGTHS
FROM BOTTOM OF
PAN HEAD TO END O
F
THREADED SHAFT
FROM TOP OF FLAT
HEAD TO END OF
THREADED SHAFT
Figure 2. Screw Sizes Used in Assembly.

8
Standoffs
A number of threaded standoffs are used. As with the screws and washers, be sure you use the correct size as
specified in the text. Standoff lengths are measured from end to end as shown in Figure 3. Standoffs threaded for
2-56 and 4-40 screws are used.
LENGTH AS SPECIFIED IN TEX
T
THREAD SIZE AS
SPECIFIED IN TEXT,
EITHER 4-40 OR 2-56
Figure 3. Typical Standoff.
Lock Washers
Two types of lock washers are used in the K3 (see Figure 4). It is important that you use only the type specified
and put the washers exactly where indicated. Failing to use the correct type may result in short circuits to nearby
circuit traces. Adding washers or placing the washers in the wrong position may cause parts to fail to fit together
properly.
SPLIT INSIDE TOOT
H
Figure 4. Lock Washers.