ELECRAFT K1 TRANSCEIVER BAND WPM + E LECRA F T RIT/XIT TX DISPLAY ATTEN 1 FILTER RX MENU WPM - K 1 TR ANS C EIVER EDIT + 2 ATTEN AF GAIN RIT - MSG + XIT TUNE O W N E R’S M A N U A L
ELECRAFT K1 Multiband CW Transceiver Owner’s Manual Revision I, April 15, 2011 Copyright 2011 Elecraft, LLC All Rights Reserved Elecraft www.elecraft.com P.O.
ELECRAFT 2 Table of Contents 1. INTRODUCTION.................................................................................................................................................................................... 3 2. SPECIFICATIONS ................................................................................................................................................................................ 5 3. PREPARATION FOR ASSEMBLY......................................................
ELECRAFT 3 1. Introduction The K1 is a versatile, low-power CW transceiver that covers two or four builder-selected HF bands. It provides 5 watts or more of power output; excellent receiver sensitivity and selectivity; and many useful operating features, including instant band selection, receive and transmit incremental tuning (RIT/XIT), digital display, configuration menu, and multiple crystal filter bandwidths.
4 ELECRAFT Customer Service Information Technical Assistance If you have difficulty with kit construction, operation, or troubleshooting, we’re here to help. You may be able to save time by first consulting our web site, www.elecraft.com, or by posting your question on the Elecraft e-mail forum, elecraft@qth.net. Telephone assistance is available from 9 A.M. to 5 P.M. Pacific time (weekdays only) at 831-763-4211. You can also send e-mail to support@elecraft.com.
ELECRAFT 5 2. Specifications Measurements were made using a 14-V supply and 50-ohm load. Transmitter General Size (H x W x D) Cabinet Overall 2.2 x 5.2 x 5.6" (5.6 x 13 x 14 cm) 2.4 x 5.2 x 7.1" (6 x 13 x 18 cm) Weight 1.4 lbs. (0.6 kg), excluding options Supply voltage 8.5 to 15 VDC Current drain Receive Transmit 1 55 mA typ. (no signal) 700-900 mA typ.
ELECRAFT 6 3. Preparation for Assembly Overview of the K1 The K1 uses modular design for ease of assembly and troubleshooting. The chassis is made up of five pieces (Figure 3-1), any of which can be removed individually. The RF power amplifier transistor uses the right side panel as a heat sink, so there is no separate heat sink element. Each side panel includes a 10-32 threaded PEM nut as a mounting point for the KTS1 tilt stand.
ELECRAFT 7 Board-to-board Connectors The circuit boards in the K1 plug in together using board-to-board connectors, which eliminates nearly all hand wiring. Gold-plated contacts are used on these connectors for reliability and corrosion resistance. Figure 3-3 shows a side view of the PC boards and board-to-board connectors. As can be seen in the drawing, the Front Panel board has a connector J1 which mates with right-angle connector P1 on the RF board.
ELECRAFT 8 Unpacking and Inventory Handling Integrated Circuits and Transistors This kit uses integrated circuits (ICs) and transistors that can be damaged by electrostatic discharge (ESD). Problems caused by ESD can often be difficult to troubleshoot.
ELECRAFT 9 Identifying Capacitors Soldering and Desoldering Small-value fixed capacitors are usually marked with one, two, or three digits and no decimal point. If one or two digits are used, that is the value in picofarads (pF). If there are three digits, the third digit is a multiplier. For example, a capacitor marked "151" would be 150 pF (15 with a multiplier of 101). Similarly, "330" would be 33 pF, and "102" would be 1000 pF (or .001 µF).
ELECRAFT 10 Desoldering Assembly Notes The printed circuit boards used in the kit are double-sided, meaning that they have circuitry on both sides. The component mounting holes are plated-through to complete electrical connections between the two sides. Each step in the assembly process is accompanied by a check-box: Removing components from double-sided boards can be difficult, since you must get all of the solder back out of the hole before a lead can be removed.
ELECRAFT 11 4. Filter Board This section applies only to the two-band K1 Filter board. If you have a four-band K1, refer to the assembly instructions in the KFL1-4 manual. The Filter board determines the K1's bands of operation. A photograph of the completed board appears in Appendix D. Open the bag of components labeled KFL-2 and sort the parts into groups. Identify components using the photographs in the Filter board parts list in Appendix A.
ELECRAFT 12 Install the capacitors listed below. The list shows the capacitance value, followed by the labeling (in parentheses). After installing each capacitor, bend the leads outward at about a 45degree angle to hold it in place until it is soldered and trimmed. __ C29, .001 (102) __ C30, .001 (102) At this point you’ll need to choose whether to set up the VFO for 80-kHz or 150-kHz coverage (approx.).
ELECRAFT 13 Cut two 3/4" (19 mm) bare wires (use component leads). Referring to Figure 4-1, insert bare wires into the grounding holes provided near X1 and X2. Fold each wire over the top of the crystal and solder it on top. Keep soldering time below 5 seconds at a time; if it takes longer, your iron may not be hot enough, or your iron tip may not be making good contact with the crystal can. Solder and trim the wires on the bottom of the board.
ELECRAFT 14 i In the following steps you’ll install toroidal inductors L9L12 (type T37-6 cores). They must be wound as indicated in the instructions, or the transceiver will not operate correctly. Use only the number of turns specified. It is not necessary to attempt to precisely match the inductances specified in the parts list. Verify that the turns of L9 are not bunched together. They should be evenly spaced, and should occupy about 80-90% of the core.
ELECRAFT 15 i The connectors to be installed in the following steps must be positioned correctly to avoid intermittent or unreliable operation. Before attempting to install multi-pin connectors, review the information on page 7. Cut a 1" (25 mm) length of insulated hookup wire. Strip about 1/8" (3 mm) of insulation off of each end. Install this wire between pins 2 and 10 of J2, in the upper righthand corner of the board (Figure 4-5).
ELECRAFT 16 Insert U1 into its socket, with the notched or dimpled end of the IC aligned with the notched end of the PC board outline. Figure 4-7 shows an 8-pin IC; U1 is similar but has 18 pins.) Press U1 down into the socket as far as it will go. Visual Inspection Using the parts placement drawings in Appendix F, re-check the orientation of the relays (K1, K2, K3) and U1. i Notch Pin 1 About 90% of all problems with kits are caused by poorlysoldered component leads.
ELECRAFT 17 5. Front Panel Board The liquid-crystal display (LCD), switches, and other controls are located on the Front Panel board, as well as the microcontroller. See Appendix D for photos of the completed assembly. Open the bag labeled FRONT PANEL and sort the parts into groups. Observe anti-static precautions with ICs and transistors. Locate the front panel PC board, which is labeled "K1 FP" along one edge.
ELECRAFT 18 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 shown). The leads of the switches will just be visible on the bottom of the board. Proper switch height is important for maintaining an even appearance. Once S1 is seated correctly, solder the leads on the bottom side of the board. Leave the spacing tool in place while soldering. Install S3, once again using the switch spacing tool to adjust the switch height.
ELECRAFT 19 i Before handling ICs and transistors in the following steps, touch an unpainted, grounded metal surface. Locate transistor Q1 (type 2N4124), which has a small, 3-lead TO-92 package. Q1 and other TO-92 devices may have either of the two shapes shown in Figure 5-4. The right-hand illustration shows a "modified TO-92" package, which may be labeled on either the front or back side. The large flat side of each device will be aligned with the flat side of its component outline.
ELECRAFT 20 Open the bag labeled MISCELLANEOUS and empty the contents into a shallow box or pan. This will prevent loss of any of the small hardware while allowing you to locate items as needed. Top Side i Five sizes of 4-40 screws are used. All are black anodized except the 1/4" and 3/8" pan heads (see Figure 5-5). The length of flat-head screw is measured from the top of the head. Pan-head, 1/4” (6 mm) Figure 5-6 Pan-head, 3/8” (9.
ELECRAFT 21 Inspect the solder side of U1's socket on the top side of the board. Make sure all pins are soldered, with no cold solder joints. Using a DMM, check every pair of adjacent pads on U1 on the top side of the board (pins 1-20 and 21-40). The resistance between pads should be over 1000 ohms (1 k) in all cases, and may read infinite on your DMM (often indicated by a flashing display). i Caution: the LCD (DS1) and its pins are fragile.
ELECRAFT 22 Visual Inspection Type 1 Using the parts placement drawings in Appendix F, re-check the orientation of the LEDs (D1 and D2), LCD (DS1), and all ICs. Type 2 Examine both sides of the PC board closely for solder bridges, cold solder joints, or unsoldered components. CCW Resistance Checks CW Set both potentiometers to their mid-points. Resistance > 100 k > 100 k > 100 k > 100 k 90-200 k > 100 k < 50 k 15-18 k > 100 k Front Panel Final Assembly Cut three 1.
ELECRAFT 23 Install caps on switches S1 through S6. S3's cap is square, while the others are rectangular, as shown in Figure 5-10. The caps are installed by pressing them onto the switch plungers. After removing any masking tape, turn the front panel face up, with the Elecraft logo at the top. Position the clear plastic LCD bezel over the large LCD opening, then secure it with four 2-56 screws (stainless steel) as shown in Figure 5-11.
ELECRAFT 24 Insert the Front Panel PC board assembly into the front panel (Figure 5-12). The push-button switch caps should protrude slightly. i The Allen wrenches are located in a small bag with the MISCELLANEOUS items. These wrenches may have been oiled during manufacturing. Remove the wrenches and wipe off the oil, if any, then discard the bag. Use the larger Allen wrench (5/64" [2 mm]) to tighten the two set screws on the large knob.
ELECRAFT 25 6. RF Board, Part I In Part I, the VFO (variable-frequency oscillator) and receiver sections will be assembled. Open the bag labeled RF and sort the components into groups. Observe anti-static precautions when handling transistors and ICs. Locate the RF board and orient it as shown in Figure 6-1. This illustration shows the major areas of the board. Receiver and VFO circuits occupy the front half; transmitter and T-R switch stages use the rear half. The Filter board plugs into J6, J7, and J8.
ELECRAFT 26 Locate a 2-D fastener and hold it vertically (Figure 6-3a). Looking at a side with two holes, note that the holes are offset from the center. The PC board outlines for the 2-D fasteners have a matching offset, which will aid in installing them in the next step. i In the steps that follow you’ll install the connectors that mate with the Filter and Front Panel boards. These connectors must be installed properly to ensure reliable mechanical connection.
ELECRAFT 27 Position 20-pin male right-angle connector P1 on the bottom of the RF board (Figure 6-5), but do not solder yet. Review Figure 3-3 for correct placement. The short ends of the bent pins are inserted into the holes, and the long ends are parallel to the board. Top of board Front edge Install the resistors listed below. R23 is at the left-front edge. __ R23, 1.5 Ω (BRN-GRN-GOLD) ⇒ __ R21, 2.7 k (RED-VIO-RED) __ R2, 100 k (BRN-BLK-YEL) __ R17, 120 (BRN-RED-BRN) __ R14, 2.
ELECRAFT 28 Install the resistor networks listed below, checking the part numbers carefully before installation. Orient the black dot or bar on each network towards pin 1 of its component outline. __ __ __ __ __ __ RP3, 47 k, 10 pins (10A3473G, 103C104, or 770103473) RP1, 100 k, 8 pins (8A3104G, 83C104, or 77083104) RP2, 100 k, 8 pins (8A3104G, 83C104, or 77083104) RP6, 27 k, 6 pins (6A3273G, 63C273, 4306R-102 LF273 or 77063273) RP4, 3.9 k, 6 pins (6A3392G, 63C392, 94163392P or 77063392) RP5, 3.
ELECRAFT 29 Push the black keycap onto S1’s plunger until it snaps. i Transistor Q4 (ZVN4424) is labeled on the back (the side with smaller area), which is different from most TO-92 devices. The labeled side of Q4 must face the power switch, S1. Install Q4 (ZVN4424A) in the back-right corner near S1. Install the DC input jack, J4, at the back edge. The 3 leads on the jack must be lined up with the slot-shaped holes in the component outline.
ELECRAFT 30 i Electrolytic capacitors are mounted vertically, so their PC board outlines are circular. The (+) lead must be installed in the hole marked with a "+" symbol. The (+) lead is usually longer than the (–) lead, and the (–) lead is identified by a black stripe (Figure 6-6). - + Figure 6-6 Install the electrolytic capacitors listed below. They must be seated as close to the PC board as possible to avoid interfering with option modules that you may install later.
ELECRAFT 31 Turn the K1 off and disconnect the power supply. Install the headphone jack, J2, on the small board extension near the front-left corner. The pins on J2 are not very long, so they will be nearly flush with the bottom of the board. Solder the pin closest to the front edge first (ground), then verify that the jack is seated flat on its plastic nubs before soldering the other pins.
ELECRAFT 32 Locate the dark gray (ferrite) toroid cores. You should have four smaller cores (type FT37-43) and one larger core (FT50-43). The three inductors to be wound in the following steps, L2, T1, and T2, all use the smaller ferrite cores. Install T1 flat against the board, between U1 and U2. Insert the leads into its numbered holes as shown by the component outline. Pull the leads taut on the bottom, then solder and trim.
ELECRAFT 33 On the top side of the RF board, locate the hole identified as (A) in Figure 6-9. (The label "S1" appears near the hole.) (B) (B) (A) i When working with the side panels in the following steps, place a soft cloth on your work surface to protect the paint. (A clean anti-static mat will also suffice.) Locate the two side panels and arrange them as shown in Figure 6-10, with the inside surfaces facing up. The right side can be identified by the presence of an extra hole as shown.
ELECRAFT 34 i Flat-head screws are more easily damaged than panheads. Do not use excessive force when tightening them. Attach two 2-D fasteners to each side panel at the locations indicated in Figure 6-10. (Make sure that the holes are countersunk; if not, you may be working with the wrong side of the panel.) Use one 3/16" (4.8 mm) flat-head screw to hold each 2-D fastener to the side panel (Figure 6-11). The two unused holes on each fastener must be offset away from the side panel as shown.
ELECRAFT 35 With the assembly upside-down or resting on one side, plug the front panel assembly into the RF board (Figure 6-13). Connector J1 on the bottom of the front panel PC board mates with P1 on the bottom of the RF board (indicated by an arrow below). i The switches should now be accessible, and the headphone jack should be even with the front panel. Also, the LEDs above the VFO knob should be visible.
ELECRAFT 36 7. Alignment and Test, Part I In this section you’ll become familiar with K1 operation, while testing control circuits and aligning the VFO and receiver. The Tap/Hold Rule Each of the push-button switches on the front panel has two functions, one activated by a TAP (short press) and the other activated by a HOLD (long press, about 1/2 second). The upper label on each switch shows the TAP function (white lettering), and the lower label shows the HOLD function (yellow lettering).
ELECRAFT 37 Sidetone Generator and Audio Amplifier Keyer Plug in a pair of stereo headphones, and rotate the AF GAIN control clockwise to about 9 or 10 o’clock. Note: If you don’t have a keyer paddle, you can still test the DOT and DASH lines by using test clips to touch them to ground. Tap M E N U . The first menu entry will be displayed: O UT (transmit power output). Tap W P M + to select the next menu entry, S T L (sidetone volume). (Lower-case "t" is used.
ELECRAFT 38 VFO Alignment VFO Range Test Turn the K1 off and disconnect the power supply. Two different capacitors are supplied for setting the approximate VFO range: C2 (68 pF disc) and C2A (120 pF polystyrene). 68 pF provides a range of about 80 kHz; 120-pF provides a range of about 150 kHz. Other values can also be used (builder-supplied). Based on your VFO range selection (page 12), install the appropriate capacitor at C2. Save the other for possible future use.
ELECRAFT 39 Band Assignments Receiver Alignment To see the correct display when you tap B A N D , you’ll need to specify which bands are covered by your Filter board. This section applies only to the two-band Filter board. If you have a four-band Filter board installed, refer to the KFL1-4 manual, page 17. If you re still in the C A L menu entry, tap M E N U to exit. Locate the B1 menu entry (note that the "b " actually appears in lower-case).
ELECRAFT 40 Band-Pass Filter Alignment On the Filter board, there are premix filters and RF filters for each band, as shown in Figure 7-2. Each filter has two slug-tuned inductors. These filters will be peaked in the following steps. Premix While listening to noise or a weak signal, peak the band-2 Premix inductors, L3 and L4. Peak the two band-2 RF inductors, L7 and L8. Re-peak L3 and L4, then L7 and L8, until no further improvement is noted.
ELECRAFT Operating Frequency Calibration The operating frequency display may be off by up to 10 kHz until calibrated, due mostly to variations in the crystals on the Filter board. Accuracy of +/- 100 Hz can be obtained. Note: The approximate lower band edges in MHz are as follows: 3.50, 7.00, 10.00 or 10.10 (selected earlier), 14.00, 18.05, 21.00. Select the lower-frequency band using B A N D . Also select the narrowest filter (FL 3 ) by holding X F I L .
ELECRAFT 42 8. RF Board, Part II In this section you’ll install the transmitter components. Turn off the K1 and disconnect the power supply. Unplug the Filter board and set it aside. i If you have difficulty installing components in the remaining assembly steps, unplug the Front Panel assembly and remove the side panels. Install the following capacitors, starting with C3, which is in the back-left corner of the RF board. __ C3, 10 (10) ⇒ __ C15, .001 (102) __ C14, .001 (102) __ C76, .01 (103) __ C44, .
ELECRAFT 43 i TO-220 package transistors Q6 and Q7 look identical, but are different types. Locate the 2SC1969 (labeled "C1969"), Q7, and set it aside. The remaining transistor, Q6, will be either a 2SC2166 (C2166) or a 2SC5739 (C5739). This transistor will be installed first. Attach a self-adhesive thermal pad to the PC board on top of the component outline for Q6. The hole in the thermal pad must be aligned precisely with Q6's mounting hole on the board.
ELECRAFT 44 Bend the center lead of Q7 slightly away from the side panel, forming it as shown in Figure 8-3. Hold the right side panel up to the right edge of the RF board. Insert Q7's leads into their pads while guiding the panel into position. Secure the right side panel to the RF board using two 3/16" (4.8 mm) flat-head screws. T3 is wound on an FT37-43 core (dark gray), the smaller of the two cores remaining. Start with the 1-2 winding, which uses 12 turns of red enamel wire (9", 22 cm).
ELECRAFT 45 i T4 uses a bi-filar winding, which means that two wires are wound on the core together. The wires for the two windings will be twisted together (see Figure 8-5). If you plan to operate the K1 on 80 meters, and your K1 RF board is revision D or earlier, you may need to make a minor modification to the PC board. Please refer to the errata sheet included with the K1B80 (80-m Band Kit).
ELECRAFT 46 9. Alignment and Test, Part II In this section you’ll align and test the transmitter stages. Turn off the K1. Plug in the Filter board. Attach the side panels, then plug in the Front Panel assembly. Connect an antenna that is adequate for receiver testing. Plug in a pair of stereo headphones or a speaker at J2. Make sure the Filter board is not installed. Place the power switch, S1, in the OFF position (out). Connect a 12 to 14-V, 1-amp power supply (or battery) to J4. Turn on the K1.
ELECRAFT Band 1 Alignment If a 4-band Filter board is in use, refer to the KFL1-4 manual, page 19. 47 Band 2 Alignment Switch to band 2, and set the VFO to about mid-band. All filters are shared between receiver and transmitter, so transmit alignment should already be close. However, it's important to repeak the filters on transmit. An analog wattmeter, ham-band receiver, or the K1’s built-in digital wattmeter can be used.
ELECRAFT 48 1. Final Assembly Remove any masking tape from the top and bottom covers. Use the technique described on page 23. Remove and save the hardware supplied with the antenna and key jacks. The components on the bottom of the board must have an overall height of no more than about 0.2” (5 mm) above the PC board. Fold down or re-solder components if necessary. Install the bottom cover by sliding it over the rear-panel controls. Secure it to the rest of the assembly using six 3/16" (4.
ELECRAFT 49 Cut a 5" (13 cm) length of two-conductor speaker cable. Remove 1/4" (6 mm) of insulation from the wires at both ends. Solder crimp pins to the two wires at one end (Figure 10-3). Copper wire Pin 1 side Plug the internal speaker cable into P2 on the RF board. The connector is keyed and can only be plugged in one way. i When you install the top cover in the next step, route the speaker cable along the right side of the cabinet, away from the pins of the microcontroller (front panel, U1).
ELECRAFT 50 11. Operation This section explains how to set up and operate the K1. We suggest you read the first few pages as an overview, then follow the tutorial, which starts on page 54 (Basic K1 Operation). There's also a Quick Reference, Appendix G, which shows the locations of front-panel controls and describes each of the menu entries. Connections Power Supply You can use any 9-15 V DC power supply; current drain is about 0.5-1A on transmit. A mating DC power connector is provided with the kit.
ELECRAFT 51 Controls and Display Switch Functions LCD T A P a switch to access its upper function; H O L D a switch for 1/2 second to access its lower function. All functions are listed below. The 3-digit LCD (liquid crystal display) shows the operating frequency or relative signal strength (S-meter) on receive, power output on transmit, menu parameters, and status information. Decimal Point: The decimal point is flashed when RIT or XIT is enabled. This acts as a reminder that RIT or XIT is on.
ELECRAFT 52 Using the Menu To access the menu, tap M E N U . Scroll menu entries by tapping W P M + / W P M - . Hold E D I T to display a menu entry's parameter, which can then be changed by tapping W P M + / W P M - . Tap M E N U to return to scrolling. Another tap of M E N U will return you to normal operation. If a parameter appears as "- - ", the associated option is not installed.
ELECRAFT 53 Calibration Functions Operating Frequency Calibration and VFO Test (CAL) The FL x , Bx , C A L , and S I G menu entries are typically used during initial test and setup of the K1. Bx and C A L are also used whenever you plug in a different Filter module to allow the K1 to display the correct frequencies. This menu entry is used to calibrate the operating frequency display, or to align the VFO. (VFO test and alignment is covered in detail on page 38.
ELECRAFT 54 Basic K1 Operation Transmitter Setup Self-Test: A number of tests are done at power-up. If you see an error message (such as E4 2 ), refer to Troubleshooting. Display Mode: During transmit the LCD normally shows a bargraph (1 bar per watt). If you select supply voltage display mode (using D I S P L A Y ), the power supply or battery voltage will be shown, flashing slowly. In TUNE mode, power is shown in watts (see below). SWR can be displayed if the KAT1 ATU is installed.
ELECRAFT RIT and XIT RIT (receive incremental tuning) can be used to fine-tune the pitch of a received signal without affecting your transmit frequency. This is most often used when a station calls you off frequency. To turn on RIT, tap R I T . The RIT LED (green) will turn on, and the LCD's decimal point will flash slowly. You can then use the OFFSET control to vary the receive frequency. XIT works similarly to RIT, except that the transmit frequency is varied with the offset control.
ELECRAFT 56 Recording and Playing Messages The K1 provides two CW message memories of 90 bytes each. CW messages can only be recorded using a keyer paddle connected directly to the K1's key jack. Set I NP to P Dn or P Dr . Messages are stored in EEPROM, so they won't be lost when power is turned off. To Record a Message: Hold R E C , and when prompted with 1 - 2 , tap either 1 or 2 . The display will then show REC 90, indicating that 90 bytes of storage are available in this message buffer.
ELECRAFT 57 Advanced Operating Features K1 Options Programmable Function Switch (XIT [PFn]) Four- and Two-Band Filter Modules (KFL1-4, -2) By default, the X I T [ P F n ] switch turns XIT on and off. Alternatively, this switch can be set up as a direct edit shortcut to any menu entry. To program the switch function, enter the menu and scroll to P Fn , then change the parameter to the desired menu entry. Setting it to NO R (normal) assigns the switch to XIT.
ELECRAFT 58 12. Circuit Details While reading this section, refer to the Block Diagram (Appendix B) and schematics (Appendix C). Overview The K1 is a compact, high-efficiency CW transceiver capable of operating over a wide range of frequencies. The two (or four) bands of operation are determined by a single plug-in filter module, allowing the builder to swap in a different set of bands if desired. The firmware will recognize whether a two- or four-band board is installed.
ELECRAFT virtue of an intermediate voltage supplied by op-amp U5A. To turn both elements of D1 off, pin 4 is made an input. The states of the DOT and DASH lines are sampled on analog input RA3 (pin 5). If both DOT and DASH are open, the voltage at RA3 will be about 6 V. If both are closed, the voltage will be 0 V. If only one paddle is closed, an intermediate voltage results, either 2 V or 4 V. (See RF board, sheet 2.
ELECRAFT 60 Q9 isolates the VFO from noise pickup on the frequency counter line. U5 and U6 double-regulate the VFO supply voltage for improved stability. Since U5 is a low-dropout 8-volt regulator, the K1's supply voltage can drop to as low as about 8.5 V without affecting the VFO frequency. U6 is a 6.0-volt regulator with a very tight tolerance of 2.5%. U4 amplifies the received audio signal and sidetone to headphone or speaker level.
Appendix A PICTURE K1 Packing Box Parts List Designators Revised 11-30-2000 Misc. RF PC board E100094 1 B1 Left side panel E100097L 1 B2 Right side panel E100097R 1 B3 Front panel, silkscreened E100096SS 1 B4 Bottom cover, silkscreened E100098SS 1 B5 Top cover E100099 1 Bag, Misc.
Appendix A PICTURE K1 Packing Box Parts List Designators Revised 11-30-2000 Misc (in envelope) Acrylic display bezel; for LCD (Front Panel) E100108 1 Misc (in envelope) Serial Number Label E980024 1 SP1 Speaker, 8-ohm, 1 watt E980032 1 KN1 Large knob, 1.25" dia, 0.25" shaft; Rogan #RB-67-3-M E980021 1 KN2, KN3 Small knob, 0.
Appendix A PICTURE K1 Front Panel Board Parts List Designators Description Part Number QTY C1, C2 82 pF NPO disc; label: "82" E530038 2 C5, C6 .01 µF, monolithic; label: "103" E530009 2 C4 .047 µF, monolithic; label: "473" E530025 1 D1 LED, dual, orange/green; LiteOn LTL-298WJ (Digikey 160-1037) E570000 1 D2 LED, yellow; LiteOn LTL-4253 (Digikey 160-1133) E570001 1 D3 Diode (not used at present) DS1 3-character, 7-segment LCD (V.L.
NOTE: Many of the resistors are supplied attached to strips of tape in assembly order, however some are also supplied loose Be sure to check the color codes of all resistors during assembly to be sure you're installing the correct part.
Appendix A PICTURE K1 Front Panel Board Parts List Designators Description Part Number QTY S1-S6 Switch, push button E640005 6 U1 PIC16C77MCU, programmed ("K1"), 40 pins E610005 1 U2 U3 U5 MAX518BCPA; Dual D/A converter, 8 pins Alt: MAX518ACPA 24LC04B/P; EEPROM, 8 pins (alternate: 24WC04P) LM358, 8 pins E600013 E600021 E600010 1 1 1 U4 X1 Misc. Misc ZR78L06C; Voltage regulator, 6V, 2.5% (Zetex); TO-92 plastic, 3 pins 4.
Appendix A PICTURE K1 RF Board Parts List Designators Description Part Number QTY C14, C15, C16, C19, C22, C28, C29, C51 .001 µF, monolithic; label: "102" E530001 8 C4, C6, C17, C18, C21, C23, C25, C36, C37, C40, C43, C44, C45, C47, C48, C49, C58, C60, C64, C66, C72, C74, C75, C76 .01 µF, monolithic; label: "103" E530009 24 C24, C30, C32, C41, C50, C56, C57, C61 .047 µF, monolithic; label: "473" E530025 8 C34, C46, C52, C55, C68, C70, C71, C73 0.
Appendix A PICTURE K1 RF Board Parts List Designators Description Part Number QTY C13, C20 Ceramic trimmer capacitor, 8-50pF E530000 2 D2, D15 1N5711 Shottky diode, small glass pkg E560004 2 D5, D9-D14, D18 1N4007 PIN diode, large plastic pkg, black E560001 8 D19 1N4753 zener diode, 36 V, 1 watt E560007 1 D1, D17 1N4148 switching diode, small glass pkg E560002 2 D16 SB530 Shottky diode, 5A, very large plastic pkg (black) (alternate: 1N5821) E560003 1 D4 MV209 E560006 1 D3, D
Appendix A PICTURE K1 RF Board Parts List Designators Description Part Number QTY Keyer Jack, threaded bushing, Stereo, vertical mount J3 E620027 1 E620028 1 J2 Headphone jack, non-threaded, Stereo, with switch, horizontal mount J9, J10 2-pin, pads only (coax soldered to connections--see text) K1 Latching Relay, 5V; in plastic tube E640001 1 L1 T50-6; Toroid (yellow), approx. 4.
Appendix A PICTURE K1 RF Board Parts List Designators Description P1 P2 P3 20 x 1 ,male, RA; 20 pin male, right angle. To Front Panel, J1 2 pin, male, 0.1" conn with locking ramp; for speaker 3 pin, male, 0.1" conn.
Appendix A PICTURE K1 RF Board Parts List Designators Description Part Number QTY R10, R33 R7 R12, R28 R1, R26, R27, R39 R5, R6, R9, R14, R21, R24 R4 R20 R19 R2, R25, R34 R13 470 Ω, 1/4W, 5%; color code: yellow-violet-brown 680 Ω, 1/4W, 5%; color code: blue-gray-brown 820 Ω, 1/4W, 5%; color code: gray-red-brown 1.8 k, 1/4W, 5%; color code: brown-gray-red 2.7 k, 1/4W, 5%; color code: red-violet-red 5.
Appendix A PICTURE K1 RF Board Parts List Designators Description Part Number QTY U4 LM380N-8, 8 pin DIP, AF amplifier E600019 1 U3 LM386N-1, 8 pin DIP, AF amplifier E600022 1 U9 LT1252, 8 pin DIP, VFO Buffer; TX Buffer E600020 1 U1, U2, U7, U8 SA602AN, 8 pin DIP, TX Mixer; Prod. Detector Alt: SA/NE612AN E600006 4 U6 ZR78L06C, 6-volt reg., 2.5%; TO-92 package, 3 pins E600017 1 W1 Jumper, RG174 coax, From J9 to J10; see text X1-X6 4.9152MHz Crystal; "ECS V4.9136" or similar.
All capacitors are NPO disc or monolithic, 5% 0.2" lead spacing. Values are in pF. * * NOTE: The 80-meter band kit also includes 10 µF electolytic capacitor C78 that is installed on the RF board.
Appendix A PICTURE K1 Misc. Bag Parts List Designators Description Part Number QTY HW #4 int.
Appendix A PICTURE Appendix A K1 Misc. Bag Parts List Designators Description Part Number QTY SPK-J1 2 pin female conn. Housing, 0.1” spacing, locking ramp. (for speaker) E620021 1 ACC-P1 2.1mm male conn.
Transistors 2SC5739 2SC1969 2N3906 ZN4424 MPSA14 2N7000 2N4124 Diodes J309 MV209 1SV149 C A S G D E B C D S C A G C A C BC E A = Anode, C = Cathode Integrated Circuits PLASTIC DIP VOLTAGE REGULATORS (DUAL-INLINE PACKAGE) 1 2 3 4 LEDs 78L06 8 7 6 5 D2 D1 LM2930T BOTTOM VIEW BOTTOM VIEW GND COUNT PINS STARTING AT PIN 1 AND GOING COUNTERCLOCKWISE (8-PIN DIP SHOWN) NOTCH NOTCH OUT GND IN CATHODE GREEN ANODE OUT IN GND ANODE ORANGE ANODE Special Symbols Elecraft = On
24 23 22 21 20 19 18 17 16 15 14 VFO Tuning COM 3G 3F 3 A 3B 2G 2F 2 A 2B 1G 1F 1 A 3 2 1 A A A DS1 F LCD G E D B F C E G B F C E D DP G 3 B C D DP Pushbutton Switches 3E 3D 3C 3DP 2E 2D 2C 2DP 1E 1D 1C 1B 1 2 3 4 5 6 7 8 9 VFO POT R19 100K 2 cw 13 6B 1 ccw R1 100K 10 11 First label corresponds to switch TAP, second label corresponds to switch HOLD. 12 S1 R14 1K BAND WPM + S4 DISPLAY FILTER C4 .
-14 dB C66 0.01 2 1 4 2 5 4 1 7 2 3 4 5 6 7 75 1 J10 R1 Q1 2N7000 G Q2 D3 L1 V+ OUT GND C64 4 IN1 V+ IN2 OUT GND GND 6R/AUX G C17 .01 Q11 J309 R23 1.5 Ω C72 .01 5 RP3 47K 6 PREMIX V3 6 7 C27 39 47K 1 2 3 4 5 6 7 8 J6 To FIL-P1 6B RFC6 C8 100µH 82 .047 RF/SMTR C34 0.1 C36 AF1 RP3 /AGC OFF 6A C68 4 2 R6 OFFSET 1 XFIL/TONE 5 2N3906 Buffer 0.1 AF2 2 Q9 C4 .01 AF Amp D 4 C26 39 C30 10µF S 8 1 2.
C45 .01 RFC4 100µH 6R_2 1 K1 (ATTN Relay) D10 1N4007 10 6A C47 .01 D13 1N4007 D11 R25 L2 2 3 4 5 6 7 8 1N4007 RFC3 J7 R4 C48 .01 + D5 C78 R34 TR2 1 1N4007 470 2 ** BUF Buffer C53 220µF 12V_2 LT1252 7 + 6 - 4 RP4 6A 4 2 C16 C76 .01 4 V+ 1 MIX V6 7 R32 33 33 Q7 2SC1969 Key/Keyer/Paddle 12V DC Aux 12 V - + J4 POWER D D18 1N4007 S Q5 J309 6A 2 RP5 3.9K PRE Transmit Attenuator RP5 RP5 PREMIX 1 D16 SB530 /DOT C14 .001 G C28 .
To ATU-P2 2 To RF-J8 4 6 8 10 J2 P3 (Note 1) 1 Premix Band-Pass Filters Band 1 C2 RF Band-Pass Filters C4 Band 1 C12 (See Note 2) C1 C5 L2 2 9 3 K1B 8 4 Band 2 C7 4 PA 5 6 7 8 1 3 5 7 9 Low-Pass Filters Band 1 C14 C11 L10 L9 C15 2 L6 L5 K2A 3 7 9 K2B 8 4 Band 2 C17 C9 K3A C19 L3 C20 L7 L4 L8 RF IN RF OUT PIC16C620A 1 2 3 Band 2 X1 4 6A X2 5 K1A 6 RY COM 7 8 7 8 XOSC C22 7 3 C23 K3B 4 Band 2 L12 U1 C27 .
T-R BUFFER XMIT MIXER * T-R BANDPASS FILTERS T-R DRIVER POWER AMP (5W) * LOWPASS FILTERS 4.915 MHz AGC RCV ATTEN. XMIT ATTEN. RCV MIXER CRYSTAL FILTER PROD. DETECTOR A.F. PREAMP 4.915 MHz 11.915 - 12.065 MHz (40 m) AF AMP * VFO 3.085 - 2.935 15.000 MHz (40 m) PREMIX KEY Common BFO 4.915 MHz BANDPASS FILTERS Transmit Receive * * On Filter PC Board MCU DISPLAY AND CONTROLS Appendix C K1 BLOCK DIAGRAM W. Burdick/E. Swartz Rev.
Appendix D. K1 Assembly Photographs Completed K1 with top cover and side panels removed; Front Panel and 2-band Filter board shown Plugged into the RF board.
Appendix E, Troubleshooting General Troubleshooting (00-19) Problem 00 Unit appears to be completely dead when power switch is turned on (no display, no audio); possible smoke, hot components, etc. General Troubleshooting Procedure Look for your problem in the Troubleshooting Tables. Closely examine PC boards for poor solder joints and incorrect, broken or missing components. Follow the step-by-step receiver and transmitter Signal Tracing procedures at the end of this section.
27 Filter board not plugged in, or I/O controller (FIL-U1) communication problem Display and Control Circuits (20-39) Problem 20 Regulated voltage(s) incorrect 21 General problem with switches or potentiometers 22 +6A or +6B voltages too low (< 5.7V) 23 +8V too low (< 7.5V) 24 LCD or LED problem 25 Relay Problem 26 Possible MCU problem Troubleshooting Steps DC input voltage must be > 8.5V Remove all option boards and re-check If +6V is too low (< 5.
VFO and Premixer (40-59) Receiver (60-79) Problem 40 General VFO problem; frequency jumps or drifts Problem 60 Low (or no) audio output from receiver, or general receiver gain problem 41 Can't tune VFO (or RIT/XIT offset) 42 VFO inductor not installed or VFO not oscillating 45 VFO tunes the wrong way 46 VFO or RIT/XIT range is too large, too small, or shifted low/high Troubleshooting Steps Note: Some VFO drift will always be present due to aging of compone
88 Power output fluctuates Transmitter and Keyer (80-99) Problem 80 General Transmitter problem 86 Power output is low or zero Troubleshooting Steps If power output is too low, go to 86 If power output slowly increases during keydown, go to 88 If current drain on transmit is too high for the given power level, go to 92 If the transmitter output power seems to be unstable go to 88 If the transmitter stops transmitting by itself go to 90 If the keyer isn’t working prop
Signal Tracing + You can solve nearly all problems yourself by signal tracing using an RF probe and signal source, such as the ones shown here. .01µF 8-14VDC 22K RF Probe X1 (see text) 2N2222A, 2N3904, etc. The RF probe shown in Figure 1 converts RF signals to DC so they can be measured using a DMM. RF OUTPUT Level E1 probe tip C1 .01µF E2 R1 4.
7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. Premixer: U7, pin 4 or 5 (whichever is greater). Expected: .04-.25 V. Actual: _______. Premix band-pass filter: FIL-P1, pin 6. (FIL-P1 is an 8-pin connector on the Filter board, near the crystals. Pin 6 is the third pin from the right end.) Expected: .04-.15 V. Actual: _______. (Note: the expected voltage takes into account the de-tuning effect of the RF probe.
DC Voltage Table NOTES: Measurements listed for FIL-U1 apply only to the two-band Filter board; for 4-band Filter board voltages, refer to the KFL1-4 manual. Measurements were made with a 50-ohm dummy load connected and a supply voltage of 14 V. In general, your measurements should be within 10% of the values shown. Pins NOT listed in the table should indicate 0.0 volts DC. Pins marked with (*) are hard to measure due to noise pickup.
APPENDIX F. PARTS PLACEMENT DRAWINGS (including 2-band Filter board) J3 C13 RFC2 AUX U5 C45 D13 U9 U8 R11 C58 R35 RP5 1 U7 D10 Q5 C60 C59 C14 J6 2 J7 C75 C40 U4 Q9 + C33 C69 D4 R13 C6 C72 C18 R21 U3 1 C74 C73 C9 Q2 R17 D1 D2 C71 C70 1 3 R14 2 4 T1 + + R1 C68 Q11 C54 C20 RP1 X1 1 1 RFC9 J9 C5 X2 U2 R5 R6 D7 2 R3 T2 1 3 K1 RF Rev.
ELECRAFT K1 QUICK REFERENCE Tap once to show band, tap twice to change bands LEDs LCD Hold to select display mode: normal, S-meter, or BAT (supply voltage) RX: VFO freq or S-meter TX: bargraph, 1 bar per watt BAND RIT / XIT - GREEN / ORANGE ATTN - YELLOW RIT / XIT ELECRAFT DISPLAY MENU ATTN WPM + 1 TX XFIL RX WPM - K 1 TR ANS C EIVER EDIT Tap for WPM up, Hold for FL1/2/3 T 2 Tap for WPM down, Hold for ATTN on/off ATTN AF GAIN MSG RIT - + REC XIT [PFn] Tap for RIT on/off, hold for
