ELECRAFT K3 User manual

Elecraft •www.elecraft.com P.O. Box 69 •Aptos, CA 95001-0069 [phone] •Fax: [phone]
ELECRAFT®K3
HIGH-PERFORMANCE 160 –6METER
TRANSCEIVER
K3 KIT ASSEMBLY MANUAL
PRELIMINARY
September 10, 2007
Copyright © 2007, Elecraft, Inc.
All Rights Reserved

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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.........................................................................................................................................9
Circuit Description..........................................................................................................................................9
RF Board and Chassis Assembly Procedure................................................................................................. 11
KANT3 or KAT3 and Rear Panel.....................................................................................................................19
Circuit Description........................................................................................................................................19
KANT3 or KAT3 and Rear Panel Installation Procedure.............................................................................19
KIO3 Interface .................................................................................................................................................. 22
KIO3 Circuit Description..............................................................................................................................22
KIO3 Interface Installation Procedure .......................................................................................................... 23
Front Panel and DSP.........................................................................................................................................25
Circuit Description........................................................................................................................................25
Front Panel Assembly Procedure..................................................................................................................26
Resistance Checks......................................................................................................................................... 34
Initial Power On Check.................................................................................................................................35
KREF3 ..............................................................................................................................................................36
Circuit Description........................................................................................................................................36
KREF3 Installation Procedure ......................................................................................................................36
KSYN3..............................................................................................................................................................37
Circuit Description........................................................................................................................................37
KSYN3 Installation Procedure......................................................................................................................38
KPA3 Installation..............................................................................................................................................39
Bottom Cover....................................................................................................................................................39
Bottom Cover Installation.............................................................................................................................40
Battery BT1.......................................................................................................................................................41
Battery BT1 Function....................................................................................................................................41
Battery BT1 Installation Procedure............................................................................................................... 42
Top Cover and Speaker..................................................................................................................................... 42
Test and Calibration................................................................................................................................44
Initial Power Checks ......................................................................................................................................... 44
Synthesizer Calibration..................................................................................................................................... 45
Filter Setup........................................................................................................................................................45
Option Modules.................................................................................................................................................45
Transmitter Test................................................................................................................................................45
Wattmeter Calibration (Optional) ..................................................................................................................... 45
Reference Oscillator Frequency (Optional) ...................................................................................................... 45
KPA3 100-Watt Module Installation......................................................................................................46

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Appendix A, Illustrated Parts List ...................................................................................................... A1
Appendix B, K3 Functional Block Diagram.................................................................... .....................B1
List of Figures
Figure 1. Assembled Basic K3/10 (Less Top Cover).............................................................................................. 5
Figure 2. Screw Sizes Used in Assembly................................................................................................................7
Figure 3. Typical Standoff. ..................................................................................................................................... 8
Figure 4. Lock Washers. ......................................................................................................................................... 8
Figure 5. 2D Fastener Location on RF Board.......................................................................................................11
Figure 6. Installing 2D Fasteners on RF Board.....................................................................................................12
Figure 7. Noise Blanker Standoff Location. .........................................................................................................12
Figure 8. KNB3 Noise Blanker and KR MXR Mixer Standoff Hardware Installation. .......................................12
Figure 9. KR MXR Mixer Standoff Location.......................................................................................................12
Figure 10. Installing Q3 Hardware on RF Board..................................................................................................13
Figure 11. Installing Crystal I.F. Filters on RF Board. ......................................................................................... 13
Figure 12. RF Board Partially Assembled. ...........................................................................................................14
Figure 13. Installing the Low Power Amplifier (LPA)......................................................................................... 15
Figure 14. Installing Front Panel Shield................................................................................................................16
Figure 15. Installing KR MXR Mixer and KNB3 Noise Blanker Boards.............................................................16
Figure 16. Installing Side Panel Feet. ...................................................................................................................17
Figure 17. Installing Side Handle Mounting Hardware........................................................................................17
Figure 18. Mounting Left Side Panel.................................................................................................................... 18
Figure 19. Installing Left Side Panel 2D Fastener. ............................................................................................... 18
Figure 20. Attaching U12 and U13 to the Right Side Panel. ................................................................................19
Figure 21. Mounting the ANT1 Connector...........................................................................................................19
Figure 22. Mounting 2D fastener for KANT3 Standoff........................................................................................20
Figure 23. KANT3 Mounting Standoff................................................................................................................. 20
Figure 24. Installing the KANT3 or KAT3 Board................................................................................................ 20
Figure 25. Installing the Rear Panel......................................................................................................................21
Figure 26. ANT Connections to KANT3 or KAT3 Boards..................................................................................21
Figure 27. Installing Rear Panel Hole Plugs......................................................................................................... 22
Figure 28. Attaching Serial Number.....................................................................................................................22
Figure 29. Installing Rear Panel Ground Screw....................................................................................................22
Figure 30. Preparing Rear Panel for KIO3 Installation.........................................................................................23
Figure 31. Preparing the KIO3 Board for Installation...........................................................................................24
Figure 32. Installing KIO3 Main Board................................................................................................................24
Figure 33. Installing the KIO3 Digital I/O Board................................................................................................. 25
Figure 34. Mounting KIO3 Connector Panel........................................................................................................25
Figure 35. Preparing the Front Panel Board for Mounting, Part 1........................................................................27
Figure 36. Preparing the Front Panel Board for Mounting, Part 2........................................................................27
Figure 37. Mounting the Front Panel on the Front Panel Board...........................................................................28
Figure 38. Preparing VFO Encoders for Mounting...............................................................................................28
Figure 39. Mounting VFO Encoders.....................................................................................................................29
Figure 40. Mounting VFO A Trim Panel..............................................................................................................29
Figure 41. Installing LCD Cover...........................................................................................................................30
Figure 42. Mounting Concentric Knobs................................................................................................................ 30
Figure 43. Mounting Friction Knobs.....................................................................................................................31
Figure 44. Mounting the VFO A Tuning Knob. ...................................................................................................31
Figure 45. Mounting the VFO B Knob................................................................................................................. 32

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Figure 46. Mounting the DSP Board.....................................................................................................................33
Figure 47. Mounting the Front Panel Assembly on the Chassis. .......................................................................... 34
Figure 48. R36 Test Point. .................................................................................................................................... 35
Figure 49. U12 and U13 Test Points..................................................................................................................... 35
Figure 50. Installing KREF3 Board. .....................................................................................................................36
Figure 51. Installing KREF3 Oscillator Module................................................................................................... 37
Figure 52. Installing the KSYN3 Board................................................................................................................ 38
Figure 53. TMP Cable Connectors........................................................................................................................ 38
Figure 54. Installing KREF3 TMP Cables............................................................................................................ 39
Figure 55. Installing Standoffs on RF Board. .......................................................................................................40
Figure 56. Installing Rear Feet..............................................................................................................................40
Figure 57. Installing Tilt Stand. ............................................................................................................................ 41
Figure 58. Installing BT1......................................................................................................................................42
Figure 59. Attaching Chassis Stiffener to Top Cover...........................................................................................42
Figure 60. Mounting Loudspeaker........................................................................................................................43
Figure 61. Installing Speaker Magnet Shield........................................................................................................ 43
Figure 62. Connecting Speaker to KIO3 Board....................................................................................................44

1
Introduction
This is the assembly manual for the Elecraft K3 High Performance 160 – 6 meter transceiver modular kit.
Full details of the Elecraft K3 and its options, including specifications, installation, operation, troubleshooting
and maintenance instructions are included in the Owner’s Manual which accompanies this kit.
Even though the K3 is an advanced, multimode transceiver, you’ll be surprised at how easy this no-solder,
modular kit is to assemble. Only a few basic hand tools are needed (see page 6). Only a few pre-fabricated
cables are used in the K3. Nearly all interconnections are made through connectors mounted on the circuit
boards themselves.
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:
•Leave 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.
•Wear 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.
•Use a grounded anti-static mat on your work bench.
•If 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.
Of course, 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
FILTER(S)
KANT3
OR OPTIONAL
KAT3 BOARD
(KAT3 SHOWN)
K3 LPA
BOARD
KIO3
BOARD
KIO3
REMOTE
I/0 MODULE
KIO3 AUDIO
I/0 MODULE
AND OPTIONAL
KXV3 MODULE
(HIDDEN)
FRONT
PANEL
SHIELD
K3 RF
BOARD
(FILLS
BOTTOM OF
CHASSIS
ASSEMBLY)
K3 CHASSIS
ASSEMBLY
Figure 1. Assembled K3/10 (Less Top Cover).

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Tools and Test Equipment Required
1. #1 and #2 size Phillips screwdrivers. To avoid damaging screws and nuts, a power screwdriver is not
recommended. Use the screwdriver that best fits the screw in each step.
2. Soft cloth or clean, soft static dissipating pad to lay cabinet panels on to avoid scratching. If using cloth,
do not lay circuit boards on it. See Preventing Electrostatic Discharge Damage on page 3.
3. Nut driver or socket wrenches with screwdriver-type handle, 1/4”, 3/16” and 1/2” sizes, are
recommended. The 1/2” size is needed to tighten the nuts on the front panel controls. A deep socket or
nut driver is required. An ordinary wrench can be used, but requires care to avoid damaging the front
panel paint.
4. Allen wrenches, 5/64” (2mm) and .050”
5. Needle nose pliers.
6. Small ruler 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 voltage and resistance checks.
8. RF 50-ohm dummy load with low VSWR across the range of 160 meters through 6 meters.
9. Power supply 13 VDC nominal (11-16 V). A power cable is provided with your K3, You’ll need to
connect it to your supply: red wire to positive and black to negative.
The following tools are strongly recommended:
1. ESD wrist strap.
2. Static dissipating work pad.
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.