Elecraft K2 Owner's Manual User Manual

+++++++E L E C R A F T A=BA/BAGCNBPRE/ATTRATEMENUANT 1/2213456798RIT XIT0DISPLAYBANDMODEFXFILKEYERAF GAINBAND - +POWERRF GAINNB ANT2 PRE ATT

ELECRAFT® 9 There are six steps in the K2 assembly process: 1. Control Board assembly 2. Front Panel Board assembly 3

ELECRAFT® 99 CW Operation The K2 provides a number of features for the CW operator:  fast I.F.-derived AGC with fast/

100 ELECRAFT® Basic CW Setup Mode Selection: To place the rig in CW mode, tap the MODE switch until the mode indicator changes to

ELECRAFT® 101 Message Memories The K2 provides nine CW message memories of 250 bytes each. Playback features include me

102 ELECRAFT® SSB Operation You can receive SSB and data-mode signals with a basic K2, but transmitting in these modes requires

ELECRAFT® 103 Advanced Operating Features A number of specialized operating techniques are described in this section:

104 ELECRAFT® Reducing Current Drain for Portable Operation You can use any of the methods listed below to reduce receive-mode c

ELECRAFT® 105 Frequency Calibration Techniques The VFO is only as accurate as the 4.000 MHz oscillator on the Control b

106 ELECRAFT® Resetting the Configuration to Factory Defaults You should reset configuration data to defaults only if the K2’s EE

ELECRAFT® 107 Secondary Menu Functions To access the secondary menu, tap MENU, then tap DISPLAY. You'll see SEC. A

108 ELECRAFT® RS232 Interface Setup (PORT) Use the PORT menu entry to turn on 4800-baud RS232 communication. When PORT is ON, ta

10 ELECRAFT® Resistors, Chokes, and the Color Code All resistor and RF choke color bands are provided in the text along with th

ELECRAFT® 109 Transverter Bands (TRN1-TRN6) Six user-definable bands are provided for use with transverters. Once

110 ELECRAFT® 9. Circuit Details Before reading this section you should become familiar with the Schematics (Appendix B) and Bl

ELECRAFT® 111 Coverage of 160-10 meters is provided by a single wide-range VCO (voltage-controlled oscillator). High-si

112 ELECRAFT® Latching Relays Latching relays are used for all filter, VCO, and option switching, so there is no relay current dr

ELECRAFT® 113 Potentiometers R1, R2 and R5 (Keyer Speed, Power Out, and RIT/XIT Offset) are multiplexed onto a single A-

114 ELECRAFT® U7 provides 2 kbytes of non-volatile configuration data storage. This memory is used for VCO lookup tables, CW mess

ELECRAFT® 115 U4 provides coarse tuning (5 kHz steps). Fine steps are achieved using a 12-bit DAC (U5) to tune a voltage

116 ELECRAFT® Sheet 3: Filters and I/O Controller The band-pass and low-pass filters are switched with latching relays to minimiz

ELECRAFT® 117 10. Options The K2 can be customized using a variety of internal and external options, which are briefly

 Page1BoxandSerial#Appendix A K2 Packing Box Parts List PICTURE Designators Value Description Part Number QTY PCB3 RF

ELECRAFT® 11 In addition to the tools supplied, you will need these standard tools:  Fine-tip soldering iron, 20-40 w

 Page2BoxandSerial#AppendixA Itemsinsidebackofmanual E850011PICTURE Designators Value Description PartNumber QTYMis

 Page1Misc.,Probe,WireAppendix A K2 Misc. Bag Parts List (p/n E850004) PICTURE Designators Value Description Part Number QTY HW

 Page2Misc.,Probe,WireAppendix A K2 Misc. Bag Parts List (p/n E850004) PICTURE Designators Value Description Part Number QTY SPK-J

 Page3Misc.,Probe,WireAppendix A K2 Misc. Bag Parts List (p/n E850004) K2 Probe Assemblies Parts List (p/n E850036 envelope in E850004 Misc b

 Page1 RFAppendix A K2 RF Board Parts List (p/n E850001A and E850001B) PICTURE Designators Value Description Part Number QTY C1, C2,

 Page2 RFAppendix A K2 RF Board Parts List (p/n E850001A and E850001B) PICTURE Designators Value Description Part Number QTY C221

 Page3 RFAppendix A K2 RF Board Parts List (p/n E850001A and E850001B) PICTURE Designators Value Description Part Number QTY C44, C4

 Page4 RFAppendix A K2 RF Board Parts List (p/n E850001A and E850001B) PICTURE Designators Value Description Part Number QTY J3 2.

 Page5 RFAppendix A K2 RF Board Parts List (p/n E850001A and E850001B) PICTURE Designators Value Description Part Number QTY L31 1

 Page6 RFAppendix A K2 RF Board Parts List (p/n E850001A and E850001B) PICTURE Designators Value Description Part Number QTY T4 Bi

12 ELECRAFT® Integrated Circuits and ESD The K2 transceiver uses integrated circuits and transistors that can be damaged by ele

 Page7 RFAppendix A K2 RF Board Parts List (p/n E850001A and E850001B) PICTURE Designators Value Description Part Number QTY Q10, Q1

 Page8 RFAppendix A K2 RF Board Parts List (p/n E850001A and E850001B) PICTURE Designators Value Description Part Number QTY R75, R8

 Page9 RFAppendix A K2 RF Board Parts List (p/n E850001A and E850001B) PICTURE Designators Value Description Part Number QTY U3, U9

 Page10 RFAppendix A K2 RF Board Parts List (p/n E850001A and E850001B) PICTURE Designators Value Description Part Number QTY Z6 T

 Page1FrontPanelAppendix A K2 Front Panel Board Parts List (p/n E850003) PICTURE Designators Value Description Part Number QTY C1,

 Page2FrontPanelAppendix A K2 Front Panel Board Parts List (p/n E850003) PICTURE Designators Value Description Part Number QTY Misc

 Page3FrontPanelAppendix A K2 Front Panel Board Parts List (p/n E850003) PICTURE Designators Value Description Part Number QTY S1,

 Page1 ControlAppendix A K2 Control Board Parts List (p/n E850002) PICTURE Designators Value Description Part Number QTY C2, C20, C3

 Page2 ControlAppendix A K2 Control Board Parts List (p/n E850002) PICTURE Designators Value Description Part Number QTY P1 6P mal

 Page3 ControlAppendix A K2 Control Board Parts List (p/n E850002) PICTURE Designators Value Description Part Number QTY R1 50K Tr

ELECRAFT® 13 4. Control Board The Control board is the "brain" of the K2. It monitors all signals during rece

 Page4 ControlAppendix A K2 Control Board Parts List (p/n E850002) PICTURE Designators Value Description Part Number QTY X1 5.068M

portion of the indicated capacitance range is actually used to covereach Amateur band segment. VCO frequency can be calculated based on** Based on an

(S0 through S23 connected to DS1; only S0 and S23 shown)First switch label corresponds to switch TAP,Second label corresponds to switch HOLD.VIM-838-D

Note: Current sense resistor8V Low-Dropout Reg.K2 Control BoardVoltmeter InputQuad, 8-bit DACTo RF Board, J7To RF Board, J8To RF Board, J6Current Se

F r o n t P a n e l B o a r d Relays are shown in RESET (Vout = 0 to 4.096V)VFO Range SelectionKey/Keyer/PaddlePLL SynthesizerPLL Reference0.0

N o i s e B l a n k e rS S B A d a p t e rBFO Buffer/Attenuator2nd Xtal FilterPost-Mixer Amp.RP4, RP5: 100KK2 RF BoardProduct Det.V BIAS-XFILW.

RF Output DetectorBand-Pass FiltersI n t e r f a c eLow-Pass FiltersX v e r t e rK2 RF BoardW. BurdickBPF RelaysPRE-DRIVERVCO RelaysE. SwartzPre/Attn

Power Amplifier (PA)12:8, FT37-439:3, FT37-43K2 RF BoardPRE-DRIVERPre-DriverW. BurdickElecraftE.Swartz2SC2166 or 2SC5739(Sh. 3)(Sh. 3)2SC19692SC1969P

LOW-PASSFILTERSPOWER AMP (15W)BAND-PASSFILTERST-RCRYSTAL FILTERSAppendix C BLOCK DIAGRAMW. Burdick/E. Swartz Rev. D 1-9-04ATTEN. AND PREAMPRC

Appendix D - K2 Detail Pictures Figure 1 K2 rear right view with side panel removed.

14 ELECRAFT® Assembly The side of the Control board with most of the components is the top side. With the top side of the Cont

Appendix D - K2 Detail Pictures Figure 2 K2 Rear View

Appendix D - K2 Detail Pictures Note: Latest K2’s use a different encoder (main tuning control). Figure 3 K2 Front Panel PCB Figure 4 Det

Appendix D - K2 Detail Pictures Figure 7 PA and Low Pass Filter Detail Figure 8 PA transformer (T4), Bifilar PA collector transformer (

1 Appendix E, Troubleshooting If you have any difficulty with your K2:

2 009 LO BATT displayed  P7 on the control board may be jumpered for

3  Make sure the bottom cover is installed when doing CAL FIL and CAL

4 053 +8V too low (< 7.5V)  Inspect the entire 8V path on the RF

5 075 Possible MCU problem  Measure the voltage on pin 32 of the MCU

6 Receiver (100-149) Problem Troubleshooting Steps 100 Low (or no) au

7 140 Receiver current drain is too high  If you saw the message INF

ELECRAFT® 15 Install the 82 mH shielded inductor (L1) as shown by its component outline. Make sure the L1 is pressed do

8 (oscillating) even when connected to a 50-Ω load, you may have an inc

9 Signal Tracing Signal tracing is the primary method by which radio e

10 T-R Switch Band-Pass XMTR

11 BFO (RF, sheet 2) 1. BFO Output: Measure the signal on U11, pin 6

12 6. No-Signal AGC, Min. IF Gain: Measure the DC voltage on pin 1 of

13 4. If you don’t have an RF probe, you can build the one from Figure

14 sheet 3, lower right-hand corner). To test VPWR, set the DMM for DC

15 CONTROL BOARD (Front panel removed except ** = CAL FCTR mode w/front

16 FRONT-PANEL BOARD (* = approximate and/or may fluctuate; ** = not

17 RF BOARD (Shaded areas indicate transmit-mode voltage measurements)

16 ELECRAFT® Install and solder the electrolytic capacitors listed below, which are polarized. Be sure that the (+) lead is inst

U1 AND ITS SOCKET ARE MOUNTEDINSTALL SOCKET FIRSTFRONT PANEL BOARDON THE OTHER SIDEBEVELED CORNER2002 ELECRAFTK2 RF Rev. B16C72 (SOCKET)2002 ELECRA

XAppendix F Parts Placement Drawing, Bottom

ELECRAFT® 17 Install crystals X1 and X2 so that they are flat against the board. X1 is 5.068 MHz and is located near th

18 ELECRAFT® i The connectors used in the following steps have plastic bodies that can may melt if too much heat is applied duri

Elecraft  www.elecraft.com P.O. Box 69  Aptos, CA 95001-0069 (831) 763-4211  Fax: (831) 763-4218 ELECR

ELECRAFT® 19 i The connectors along the bottom edge of the board (P1, P2 and P3) will be installed next. It is very dif

20 ELECRAFT® i Before handling any IC, touch an unpainted, grounded metal surface or put on a conductive wrist-strap. Locate U2,

ELECRAFT® 21 Key Shaping Components (Required) Your K2 kit includes recent changes that provide an optimized keying

22 ELECRAFT® Option Components All component locations on the Control board should now be filled except for the following:  C

ELECRAFT® 23 5. Front Panel Board The Front Panel board includes all of the control and display devices that you’ll u

24 ELECRAFT® Top of board 1/16” Figure 5-3 Figure 5-3 shows a side view of a switch that is properly mounted (spacing tool not

ELECRAFT® 25 i The ICs to be installed in the next step are very sensitive to static discharge. Touch a grounded surfa

26 ELECRAFT® Install another 3/16" (4.8 mm) diameter x 1/4" (6.4 mm) long round standoff on the top of the PC board, on

ELECRAFT® 27 Install rectangular gray key caps on S1 and S3 so the key caps are parallel to the long axis of the PC boar

28 ELECRAFT® i CAUTION: The LCD and its pins are fragile—handle carefully. Do not drop the LCD on a hard surface, as it is made

2 ELECRAFT® Elecraft  www.elecraft.com P.O. Box 69  Aptos, CA 95001-0069 (831) 763-4211

ELECRAFT® 29 Uninstalled Components Check off each of the components in the list below, verifying that they are not yet

30 ELECRAFT® Front Panel Final Assembly Locate the front panel chassis piece. Place it on a soft cloth to protect the finish and

ELECRAFT® 31 Remove the brown paper backing from the other side of each piece of tape, then turn the filter/tape assem

32 ELECRAFT® Remove the insulation from four 1.5" (38 mm) lengths of green hookup wire. Install the bare wires on the bot

ELECRAFT® 33 Open the K2 Encoder Assembly Kit (K2ENCASY) and follow the instructions included with it to install the en

34 ELECRAFT® 6. RF Board Most of the K2’s receiver and transmitter circuits are located on the RF board, including filters, osc

ELECRAFT® 35 Take a moment to familiarize yourself with the RF board using Figure 6-1 to identify the major sections. I

36 ELECRAFT® Make sure that the 2-D fasteners on the edges line up with the edge of the PC board and do not hang over. If they ha

ELECRAFT® 37 Install the self-resetting fuse, F1, near D10. F1 is yellow and looks like a square-bodied capacitor. One

38 ELECRAFT® Position 20-pin male right-angle connector P1 on the bottom of the board (Figure 6-5), but do not solder P1 yet. Re

ELECRAFT® 3 1. IntroductionThe Elecraft K2 is a high-performance, synthesized, CW/SSB transceiver that covers all HF ba

ELECRAFT® 39 i When working with the side panels in the following steps, place a soft cloth on your work surface to pro

40 ELECRAFT® i Since the K2 chassis is made up of a number of individual panels and fasteners, you may need to loosen the fasten

ELECRAFT® 41 Turn the RF board/side panel assembly upside down. Check for any untrimmed component leads on the bottom o

42 ELECRAFT® Plug the Control board assembly into the RF board, with the component side of the Control board facing backwards. (

ELECRAFT® 43 Alignment and Test, Part 1 In this section you’ll test most of the circuits on the Control board and front

44 ELECRAFT® Turn the K2 off and wait for a few seconds, then turn it back on. The display should now show ELECRAFT for about tw

ELECRAFT® 45 Move the voltage select jumper (Control board, P7) toward P5. Select voltage/current display mode using th

46 ELECRAFT® Using the Calibration Functions Scroll the menu until you see CAL OFF. This is the entry point into the calibration

ELECRAFT® 47 Turn on the K2 and tap MENU to bring up the menu, then scroll to the CAL menu entry. Hold EDIT, then scrol

48 ELECRAFT® Touch the (+) lead to pin 5 of U2 on the Control board. (U2 is located just above trimmer R1. Pin 5 is the pin near

4 ELECRAFT® Customer Service Information Technical Assistance You can send e-mail to [email protected] and we will respond q

ELECRAFT® 49 Assembly, Part II In this section you’ll install the components for the synthesizer and receiver circuits.

50 ELECRAFT® Locate the PLL Upgrade kit, which should include the Thermistor PC board and all other parts listed below. Ref Des

ELECRAFT® 51 Locate all of the small glass-bodied diodes. You should have a number of 1N4148 diodes, and one 1N5711, whi

52 ELECRAFT® Sort all of the remaining capacitors by value to reduce the possibility of assembly errors in the next step. If you

ELECRAFT® 53 Solder the pins on the bottom of the RF board. Solder a pin at opposite corners first, then make sure the h

54 ELECRAFT® Solder C91 (.001 µF, "102") to the two pads shown in Figure 6-14c. Use short leads. Solder C88 (68 pF, &

ELECRAFT® 55 Find RFC14’s component outline on the RF board, near the front left-hand corner. Compare this component out

56 ELECRAFT® RFC16 is wound on an FT37-43 core (dark gray) using 16 turns of red enamel wire (12", 30 cm). Wind this induct

ELECRAFT® 57 Install T5 as shown by its component outline in the synthesizer area of the board. Figure 6-17 shows how t

58 ELECRAFT® Transformer T6 is mounted vertically, near the middle of the board. It uses a different winding technique where the

ELECRAFT® 5 2. Specifications All measurements were made using a 14.0 V supply and 50-ohm load unless otherwise indicat

ELECRAFT® 59 Review Figure 4-2 before installing Q2 in the next step. Q2 is a ZVN4424A transistor, which has a slightly

60 ELECRAFT® Note: A surface-mount RoHS compliant version of the PIN diode used at D36 is supplied pre-installed on tiny printed

ELECRAFT® 61 Insert R116's leads into L33's pads, then press the resistor down directly on top of L33. The re

62 ELECRAFT® Resistance Checks Perform the following resistance checks: Test Point Signal Name Res. (to GND) R115, right end

ELECRAFT® 63 Alignment and Test, Part II In this section you’ll test and align the PLL (phase-locked-loop) synthesizer

64 ELECRAFT® VCO Alignment In the following steps you’ll adjust the VCO inductor (L30) so that the VCO control voltage is in the

ELECRAFT® 65 BFO Test The BFO (beat-frequency oscillator) will be tested in the following steps. Switch to the 40-m ba

66 ELECRAFT® BFO Alignment The K2 uses a variable-bandwidth crystal filter, allowing the operator to set up as many as four filt

ELECRAFT® 67 I.F. Amplifier Alignment L34, located near the right front corner of the RF board, is used to peak the out

68 ELECRAFT® Install the following 1/4-watt resistors, starting with R46 which is just to the left of I/O controller U1. __ R46

6 ELECRAFT® Transmitter Power output range <0.5 W to >10 W (typ.); power setting resolution 0.1 W, accuracy 1

ELECRAFT® 69 Ferrite-bead assemblies Z1 and Z2 will be installed vertically near transformer T3 as indicated by thei

70 ELECRAFT® i TO-220 package transistors Q6, 7, and 8 look identical, but Q6 is different. Locate the two 2SC1969’s (labeled &q

ELECRAFT® 71 T2 is wound on the same core type as T1 (FT37-43). Its windings must be spaced as shown in Figure 6-26(a),

72 ELECRAFT® Locate the "binocular" (2-hole) ferrite core for T4. Wind 2 turns of green-insulated hookup wire (5"

ELECRAFT® 73 i PA transistors Q7 and Q8 (2SC1969) must be installed on the bottom of the PC board, with their metal ta

74 ELECRAFT® i If you have already purchased option kits, you may install selected option components now, as explained in the fo

ELECRAFT® 75 Install the two side panels and secure with two chassis screws each as you did in Part I and Part II. Pl

76 ELECRAFT® Keeping the K2 on its left side, slip the heat sink over the rear-panel connectors and into position (Figure 6-33).

ELECRAFT® 77 Alignment and Test, Part III In this section you’ll complete alignment and test of the K2 on all bands.

78 ELECRAFT® 40-Meter Transmitter Alignment i To align the transmitter you’ll need some means for monitoring power output as you

ELECRAFT® 7 3. Preparation for AssemblyOverview of the Kit The K2 uses modular construction, both physically and elec

ELECRAFT® 79 Receiver Pre-Alignment Since the same filters are used on both receive and transmit, it is possible to al

80 ELECRAFT® Transmitter Alignment If you did the receiver alignment, above, you may find that little or no transmit adjustment

ELECRAFT® 81 7. Final Assembly Place the top cover upside down as shown in Figure 7-1, with its rear panel facing away

82 ELECRAFT® Using a sharp tool, cut through and peel off about 1/2" x 1/2" (12 x 12 mm) of the masking material cover

ELECRAFT® 83 Finishing Touches Examine the Control board one last time to be sure that it is correctly plugged into th

84 ELECRAFT® 8. Operation

ELECRAFT® 85

86 ELECRAFT® This section of the manual explains how to set up and operate the K2. Refer to the illustrations on the previous pag

ELECRAFT® 87 Controls and Display LCD and Bargraph Meter The LCD shows the operating frequency and other information d

88 ELECRAFT® Switch Functions Each pushbutton switch as two primary functions, indicated by the upper and lower labels. TAP a sw

8 ELECRAFT® Board-to-board Connectors The circuit boards in the K2 are interconnected using board-to-board connectors, which eli

ELECRAFT® 89 Using the Menu There are two menus: primary and secondary. You'll use the primary menu far more often

90 ELECRAFT® Calibration Functions The CAL menu provides the following functions: FCTR Frequency counter CUR Programmable

ELECRAFT® 91 VFO Linearization (CAL PLL) The CAL PLL function automatically calibrates VFO fine-tuning13. You can repea

92 ELECRAFT® BFO Displays Tap BAND- to display the BFO setting for filter FL1, which will be similar to BF1t110c. The 3-digit nu

ELECRAFT® 93 CAL FIL Example (setting up all filters): Table 8-1 shows the recommended filer settings for a CW-only K2

94 ELECRAFT® Basic K2 Operation Mode Selection Tap MODE to cycle through the operating modes, noting the change in the mode indi

ELECRAFT® 95 LCD and Bargraph Configuration Day/Night Selection: For daytime outdoor operation, use the menu to select

96 ELECRAFT® Default Frequency Memories: When you first turn on the K2, each band memory is preset as follows:  VFO A is set t

ELECRAFT® 97 Power Control Turn the POWER control to set the power output directly in watts (e.g., P 5.0). The normal r

98 ELECRAFT® RIT and XIT You can turn on RIT (receive incremental tuning) by tapping RIT. The RIT annunciator then turns on. It