E L E C R A F T KX1 T R A N S C E I V E R ELECRAFT KX1 12V S1 3 5 ANT. 7 9 + RX TX RF 1 MENU 2 1.0 3 RIT BAND 0.5 2 1 SPEED EDIT RF GAIN TAP: 10 HZ / 100 HZ HOLD: 1 kHz CLR 2.
ELECRAFT KX1 Ultra-Portable CW Transceiver Owner’s Manual Revision E, May 21, 2010 Copyright 2010 Elecraft, Inc. All Rights Reserved Elecraft www.elecraft.com P.O.
ELECRAFT 2 Table of Contents INTRODUCTION .......................................................................................................................................................................................... 3 SPECIFICATIONS........................................................................................................................................................................................ 5 PREPARATION FOR ASSEMBLY .....................................................
ELECRAFT 3 Introduction The Elecraft KX1 is a compact, multi-band CW transceiver optimized for backpacking and travel use. With internal battery, internal automatic antenna tuner, log-book lamp, and plug-in keyer paddle, it offers a high level of integration. Unlike most transceivers, the KX1’s controls are located on the top of the cabinet, and the keyer paddle attaches at the front. This “trailfriendly” format is ideal for hand-held or lap-top operation, e.g.
4 ELECRAFT Customer Service Information Elecraft's 1-Year Limited Warranty 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@mailman.qth.net. Telephone assistance is available from 9 A.M. to 5 P.M. Pacific time (weekdays only) at 831-662-8345. You can also send e-mail to support@elecraft.com.
ELECRAFT 5 Specifications General Size (H x W x D) Cabinet Overall Weight Supply voltage Current drain Receive Transmit audio CW feedback on keypress Transmitter 1.2 x 5.3 x 3.0" (3 x 13.5 x 8 cm) 1.4 x 5.8 x 3.0" (3.5 x 15 x 8 cm) 9 oz. (0.25 kg), excluding options 7-14 V (8 V min. recommended) Max. power output (approx.) Spurious content -40 dB @ 3 to 4 W 35 mA typ.
ELECRAFT 6 Preparation for Assembly Overview of the KX1 The KX1 chassis consists of a top and bottom cover (Figure 1). All components, including controls and connectors, are mounted on a single printed circuit board (PCB). Only three surface-mount components are required, and these are pre-mounted to the board. The top cover is also the front panel. The controls face upward for convenient operation. The printed circuit board mounts directly behind the front panel.
ELECRAFT 7 Unpacking and Inventory Preventing Electro-Static Discharge Damage Inventory Problems caused by Electro-Static Discharge (ESD) may be very difficult to troubleshoot because damaged components may still operate somewhat rather than fail completely. We strongly recommend you take the following anti-static precautions (listed in order of importance) to avoid trouble: We recommend that you do a complete inventory, using the parts lists in Appendix A.
ELECRAFT 8 Identifying Common Resistors and RF Chokes The color bands that indicate the value of each resistor are shown in the text to help you identify each part. However, it's helpful to familiarize yourself with the color code. The color-code chart (see Figure 2) shows how to read the four color bands on 5% resistors. For example, a 1,500 ohm (1.5 k) 5% resistor has color bands BROWN, GREEN, RED and GOLD.
ELECRAFT 9 Identifying Resistor Packs Resistor packs combine a number of resistors in one component with multiple leads. They may be in-line packages with 6 or 10 leads in a row or they may be in 16-pin dual in-line pin (DIP) packages similar to many integrated circuits. Like integrated circuits, pin 1 of each component is identified by a dot near it. Some resistor packs are symmetrical. That is, they can be installed either way. However, some are not.
ELECRAFT 10 Tools You will need the following tools to build this kit: Fine-tip temperature-controlled ESD-safe soldering station with 700 to 800F tip (370-430C). Recommend a spade tip approx. 0.05” (1.3 mm) wide. Do not use a high-wattage iron or soldering gun since this can damage pads, traces, or the parts themselves. IC-grade, small-diameter (.031”) solder (Kester #44 or equivalent). i DO NOT use acid-core solder, water-soluble flux solder, additional flux or solvents of any kind.
ELECRAFT 11 Soldering and Desoldering i Use adequate ventilation when soldering; avoid inhaling smoke or fumes. Always wash your hands after handling solder, as lead residue is highly toxic. Solder Recommendations We recommend small-diameter (.02 to .03") rosin-core solder, similar to Kester type 44. Solder with 2% silver is used by some builders and will work equally well. If you use a minimum of solder, there will be no need to clean PC boards.
ELECRAFT 12 Desoldering 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. 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. To do this, you'll need solder wick (desoldering braid) and/or a vacuum desoldering tool. It also takes some practice.
ELECRAFT 13 Assembly Notes Each step in the assembly process is accompanied by a check-box: As you may have noticed already, the symbol below is used to alert you to important information: i Do not skip any steps. You may adversely affect both the performance and appearance of the kit by using the wrong assembly order. Installing Parts Follow the instructions carefully about the position of parts.
ELECRAFT 14 Assembly - Part I In Part I, the control, display, and audio stages will be assembled and tested. Later sections cover receiver (Part II) and transmitter (Part III) assembly and test. i BEFORE YOU START: 1. WEAR A GROUNDED WRIST STRAP or ground yourself briefly before touching components. You can discharge static by frequently touching an unpainted, grounded metal surface. If you haven’t done so already, open the bag of components labeled KX1 MAIN BAG and sort the parts into groups.
ELECRAFT 15 Bend the leads of resistor R8, 6.8k (blu-gry-red), 1/4 watt, at right angles close to the body. Insert the leads in the solder pad holes, and bend them out on a 45-degree angle on the opposite side of the board to hold the resistor in place. Bend the leads of resistor R28, 1.8k (brn-gry-red), 1/4 watt, to fit in the holes indicated on the board. Note that the leads should NOT be bent close to the body of the resistor like you did for R8.
ELECRAFT 16 i Save the longer clipped component leads. Several of them will be needed for grounding wires and a jumper. Install the following 1/4 watt resistors on the bottom side of the board. Their locations are in the lower right quadrant of the board when it is oriented the so outline for J1 is in the upper right corner. _ R16, 1k (brn-blk-red). _ R17 ,1k (brn-blk-red). _ R22, 300 ohms (org-blk-brn). _ R23, 470 ohms (yel-vio-brn). Locate resistor pack RP5, 100 k ohm (104).
ELECRAFT Insert RP5 with Pin 1 of the pack in the round solder pad. The round pad is farthest from the edge of the board. i Be careful to orient the resistor packs so the dot next to Pin 1 on the pack is at the round solder pad on the board. Once soldered in place, it is almost impossible to remove the pack without destroying it. Wet your soldering iron with a small amount of solder, and touch it to one of the pins to tack-solder it in place. 17 Locate resistor pack RP1, 390 ohms (391).
ELECRAFT 18 Turn the board face up so KX1 is in the upper left corner. Locate the printed outlines for diodes D2 and D3 near the center of the left edge of the board. Locate diodes D2 and D3 (1N5817). Note that there is a band on one end of the diode body. i All diodes MUST be installed with the banded end of the diode over the band on the circuit board.
ELECRAFT Turn the board face down so the printed outline for power connector jack J1 is in the upper right corner. Locate the printed outline for C39 to the left of the outline for J1 on the board. Test fit a .1 µF (104) capacitor in the solder pad holes for C39. Position the capacitor so that about 1/16” (1 mm) of lead shows above the surface of the board. If necessary, gently straighten the leads using long nosed pliers. Do not tug on the leads. Squeeze and bend them with your pliers as needed.
ELECRAFT 20 Following the same procedure, install capacitor C30, .01 µF (103) next to C31. Install capacitor C5, .1 µF (104) below the socket for U1 near the bottom edge of the board. Turn the board top face up so that KX1 is in the upper left corner. In the following steps you will install several capacitors on the top of side of the board. Be sure that the top of no capacitor is more than 5/16” (7.9 mm) above the board. Be especially careful of the larger electrolytic capacitors (see Figure 8).
ELECRAFT Insert electrolytic capacitor C38 (10 µF, 35 v) with the longer lead passing through the square solder pad with the (+) symbol next to it and the shorter lead through the round pad. Bend the leads to hold the capacitor in place against the board. Be sure that the capacitor is tight against the board and solder the leads. Use a ruler to verify that the top of the capacitor is no more than 5/16” (7.9 mm) above the board (see Figure 8).
ELECRAFT 22 Use a discarded component lead to ground the case of the crystal as follows: _ Solder one end of the lead in the ground hole near the edge of the board to on the left side of the crystal. _ Tin the top of the crystal nearest the lead with a small amount of solder. Keep the soldering time to 3 seconds or less to avoid overheating the crystal. Allow the crystal to cool if you need to apply heat more than once.
ELECRAFT Test-fit two-pin plug P1 directly below J1. Orient P1 so the locking ramp that sticks up alongside the pins is on the side farthest from J1 as shown on the printed outline on the board. Place the shell for the mating jack over the pins of P1 to protect your fingers and, while holding P1 directly against the board, solder one of P1’s pins. Check the following. If necessary, reheat the soldered pin and adjust P1. _ P1 is oriented so the locking ramp is on the side farthest from J1.
ELECRAFT 24 Test fit slide switch S2 along the edge of the board next to electrolytic capacitor C10. The switch can be oriented either way around. Note that it rests on shoulders on the three terminals that determine its height above the board. Hold S2 vertical and against the shoulders on the tabs with your finger on the slide, and tack-solder the center pin to hold it in place. Inspect the switch to be sure it is perfectly vertical and not tipped to either side.
ELECRAFT 25 Install U9 (77L06) below RP5 on the lower edge of the board using the same procedure that you used for U8 above. Be sure the top of the device is no more than 5/16” (7.9 mm) above the board. Install 3-digit LED display DS1 as follows: _ Insert the 3-digit LED display in the space bounded by resistor packs RP1, RP2, RP3 and RP4. The pins on DS1 allow it to be inserted only one way. Install transistor Q7 (2N4124). The position for Q7 is in the upper right quadrant of the board, about 1” (2.
ELECRAFT 26 Visual Inspection Resistance Checks Verify correct orientation (banded end) of diodes D2 and D3, using the parts placement drawing (Appendix F). Make the resistance checks listed below with your DMM’s negative (-) lead connected to the circuit board ground at the screw hole just above capacitor C6. Verify the correct orientation of each electrolytic capacitor. The side of the capacitor with the strip and minus ( - ) sign must face away from the + sign printed on the board.
ELECRAFT 27 Alignment and Test - Part I In this section you’ll become familiar with basic KX1 operation, while testing the control and display functions. i Microcontroller U1 is extremely static-sensitive. Wear a wrist strap or ground yourself before handling U1. Remove microcontroller U1 from its conductive foam packing and inspect the pins. The two rows of pins must be straight and parallel to each other to establish the proper pin spacing for insertion into the socket.
ELECRAFT 28 LED Tests i When testing the lamp in the following step, do NOT look directly at the white LED. It is very bright. Voltage Checks Connect your DMM’s (-) probe to circuit board ground at the screw hole next to capacitor C6. Use the (+) probe to check the following DC voltages: Switch S1 (LAMP) On and verify that D1 lights, then turn it Off. Switch S2 (POWER) On. If you see or smell smoke, or a component feels hot to the touch, switch S2 Off and disconnect the power source immediately.
ELECRAFT 29 The Tap/Hold Rule Frequency Display and Band Change 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). To highlight this in the text, we use two different typographical styles to identify switches: T AP and HOLD.
ELECRAFT 30 Assembly – Part II In this section you will assemble and test the receiver circuits. The transmitter circuits will be assembled in Part III. Position the board face up with KX1 in the upper left corner. Install R19, 1.8k (brn-gry-red), 1/4 watt to the right of RP5 near the center of the board. Turn the board over so that J1 is in the upper right corner. Install the following 1/4 watt resistors in the lower left quadrant of the board.
ELECRAFT Install the following inductors below R6 and R7 in the upper right quadrant. _ L4, micro (smaller) size, 2.2 µH (red-red-gold) _ L5, mini size, 5.6 µH (grn-blu-gold). L5 may be larger than the outline. Bend the leads to fit into the pads with the body of L5 pressed to one side against the board. Do not space L5 above the board or it may strike other components when the K3 is assembled. Turn the board face up with KX1 in the upper left corner.
ELECRAFT 32 i In the following steps you may be installing some capacitors with leads closer together than the hole spacing in the circuit board. Form the leads of these capacitors as shown in Figure 12. Be sure the top of the capacitor is no higher than 5/16” (7.9 mm) above the board (see Figure 7). Install capacitor C2, 27 pF (270) between capacitor C55 and diode D4 on the lower edge of the board. Install capacitor C21, .1 µF (104) at the lower right-hand corner of the board.
ELECRAFT Locate C45, 68 pF (68 or 680), LS 0.2. Be sure that you do not confuse this capacitor with C56, also 68 pF but with 0.1” lead spacing, that has not been installed yet. Note: C45 may be a much larger disc type, which would not fit in the location for C56. But if both are small, you’ll need to go by the lead spacing. Install capacitor C45 to the left of C46 in the upper right quadrant of the board. Install capacitor C26, 120 pF (121) pillow-style disc ceramic, about 1/2” (1.3 cm) below C45.
ELECRAFT 34 Turn the board over so jack J1 is in the upper right corner and locate the printed outline for C15 just to the left of electrolytic capacitor C7 at the center of the board. Directly above the location for C15 is one of the soldered encoder pins. If it hasn’t been trimmed already, trim it flush. Turn the board face up so that KX1 is in the upper left corner. Locate the pins for K1 in the upper right quadrant. Install C56 (68) between pins 2 and 3 of K1 as shown in Figure 13.
ELECRAFT Install electrolytic capacitor C53 (10 µF, 35 V) between diode D4 and capacitor C21 in the lower right corner of the board as follows: _ _ _ Insert the capacitor with the longer lead through the square pad with the + symbol printed next to it. Check to ensure the strip and minus ( - ) sign on the capacitor is on the side opposite the + sign on the board.
ELECRAFT 36 Install transistor Q9 (2N4124) to the right of U5. Be sure to orient the transistor according to the outline on the board (see Figure 10) and insert the transistor so that the top is no higher than 5/16” (7.9 mm) above the board. Install transistor Q8 (2N4124) as shown in Figure 14. Bend the leads so that the transistor body fits within the printed outline with the flat side facing up.
ELECRAFT Install trimmer CA as follows: _ Place a red trimmer in the CA position with the flat side of the trimmer over the flat side on the printed outline. _ Press the trimmer down against the board and spread the pins to hold it in place. Note that the adjustment for the trimmer is not visible from the top. It is accessed from the bottom through the hole in the board. _ Check to ensure the trimmer is sitting directly against the board and then solder and trim both pins.
ELECRAFT 38 Install remaining filter crystals using the same procedure you used for X2. _ X3 (4.9136) _ X4 (4.9136) _ X5 (4.9136) i Be certain the jack is mounted on the BOTTOM face of the circuit board as shown. It is very difficult to remove this jack without damaging the board if it is installed incorrectly. Solder the center pin lead and recheck the alignment.
ELECRAFT i 39 Turn the board top face up with KX1 in the upper left corner. The optional KXAT1 ATU module plugs directly into connectors J6, J7, and J8, which you’ll install in the following steps. They MUST be positioned vertically (not tilted) or the ATU module cannot be installed. _ Turn the board bottom face up with jack J1 in the upper right corner. Locate the printed outline for R2 next to electrolytic capacitor C20 on the right side of the board. This is the CENTER of the three outlines.
ELECRAFT 40 i In the following steps you’ll wind and install toroidal inductors L1 and L2. They must be wound as exactly indicated in the instructions or the transceiver will not operate correctly.3 Turn the board bottom face up with J1 in the upper right corner. Locate the printed outlines for L2 and L1 in the upper left corner near J2. Locate the four toroid cores. There are two yellow T37-6 cores and two dark gray FT37-43 cores. Use the yellow cores to make L1 and L2.
ELECRAFT Strip the insulation and tin the leads of both inductors using one of the following techniques: 1. Heat Stripping: a. Place a small amount of solder (a.k.a. a “blob” of solder) on your soldering iron. b. Insert the clipped end of the wire into the hot solder. If the iron is hot enough, you should see the insulation bubble and vaporize after 4 to 6 seconds. c. Add more solder and feed more wire into the solder as the enamel melts.
ELECRAFT 42 Your kit includes an extra 22 k resistor (red-red-orange) for use at R32. This resistor is not present on the Revision B or B1 PC boards. It must be soldered in place in the location shown below, on the bottom of the board between pins 2 and 3 of U4 (LM386N). (It could also be soldered across the pins of C19, nearby, which may be easier.) Trim and bend the leads approximately as shown.
ELECRAFT 43 Alignment and Test - Part II Temporarily mount the VFO knob on the shaft of encoder Z1. i Due to the small size of the KX1’s front panel, knobs are not appropriate for use on the RF GAIN, FILTER and AF GAIN controls. The shafts of these potentiometers, which are knurled and have molded index marks, are designed to function as knobs. Unwrap the cover and set it near the circuit board so you can see the legends identifying the controls and their functions.
ELECRAFT 44 Select the sidetone pitch menu entry (STP) using the VFO knob. Hold E D I T to turn on the sidetone and edit the pitch parameter. The pitch can be varied from 500 to 650 Hz using the VFO knob. Select the desired pitch, then tap M E N U to end parameter edit and return to STP. Tap M E N U again to return to the normal display. S-Meter and Voltmeter Displays The DISP function (holding B AN D + R I T together) selects one of three display modes.
ELECRAFT 45 Receiver Alignment Set the RF GAIN control fully clockwise. There are two receive band-pass filters to align. The trimmer capacitors are adjusted through the bottom of the board as shown in Figure 17. The 14 MHz (20 meter) filter has two adjustments, labeled 20A and 20B on the PC board, while the 7 MHz (40 meter) filter has just one, labeled 40.4 Two additional holes, labeled 30A and 30B, are provided for use with the optional 30-meter or 30/80 meter modules (KXB30 or KXB8030).
ELECRAFT 46 Locate a small flat-blade screwdriver or tuning tool for use in adjusting the trimmer capacitors. Test the tip of the tool to make sure it will through the access holes and can turn the trimmers. If the handle is not insulated, wrap the end with tape to prevent your hand capacitance from affecting the adjustment. i The trimmer access holes on the revision B and B1 KX1 PC boards are plated through and grounded.
ELECRAFT 47 Receive Current Drain Test (Optional) Operating Frequency Calibration (Optional) The current drain in receive mode is about 35 mA (with the LED menu entry set to 0, 1, or 2). If the current drain is significantly lower or higher than this, it could indicate a problem. The operating frequency display may be off by as much as ± 200Hz until calibrated, due to variations in the 50-MHz reference oscillator and BFO components.
ELECRAFT 48 Assembly - Part III In Part III you’ll install and test the transmitter and lowpass filter components. Remove the VFO knob if you haven’t done so already. Turn the board top face up with KX1 in the upper left corner. Install the following 1/4 watt resistors to the upper left of encoder Z1: _ R9, 300 ohms (org-blk-brn). _ R11, 10 ohms (brn-blk-blk) _ R31, 1k (brn-blk-red) Note: On some boards, R31 may be printed in reverse (mirror image).
ELECRAFT Turn the board top face up with KX1 in the upper left corner. Install the following capacitors in the area above encoder Z1. Be sure to check the each capacitor to ensure it is no more than 5/16” (7.9 mm) above the board. _ C42, .01 µF (103) to the left of electrolytic capacitor C35 on the top edge of the board. _ C34, .01 µF (103) to the right of electrolytic capacitor C35 on the top edge of the board. _ C41, .01 µF (103) near the upper left corner of encoder Z1. _ C43, .
ELECRAFT 50 Wind toroidal inductor L3 on one of the FT37-43 cores as follows: _ Cut a 14” (36 cm) length of red enameled wire. _ “Sew” the long end of the wire through the hole in the core for a total of 18 turns. Match the winding direction shown in Figure 18. Count one “turn” each time the wire passes through the center of the core. There are no “half” or “quarter” turns when winding a toroid. _ _ 4 3 Spread the turns around the core so the finished result looks like Figure 18.
ELECRAFT 51 Install toroidal inductor L3 and solder both leads. Check for continuity (less than 1 ohm) between the solder pads. Place the front panel (top cover) face down on a soft cloth to avoid scratching it. Do NOT attach L3 or T1 to the circuit board with adhesive or other compounds. They should be supported only by their leads. Remove the paint from around the screw holes where the short standoffs will contact the front panel as shown in Figure 21. Use sandpaper or a sharp knife.
ELECRAFT 52 Locate the thermal pad. Leave it on the backing paper while you remove the piece filling the hole near one end. Then remove the backing and place the pad on the inside of the cover over the area you sanded with the hole in the pad aligned with the hole in the cover (see Figure 22). Position the red filter over the LED display opening. Use the clear tape to secure it on the top and bottom edges as shown in Figure 23.
ELECRAFT 53 Check your kit to determine whether a 2SC2166 (metal tab) or a 2SC5739 (black plastic tab) transistor was supplied. Both transistors provide equal performance, but their installation is different because the metal tab on the 2SC2166 must be insulated from the mounting hardware. Install the transistor exactly as described in the following steps. Bend Q6’s leads into a gentle 90-degree curve (see Figure 24). Note that the flat side of the transistor faces away from the circuit board.
ELECRAFT 54 Temporarily secure Q6 to the standoff with a 4-40 flat head screw. Tighten the screw enough to hold Q6 securely and parallel to the circuit board. Use your long-nose pliers to adjust the leads so the flat side of the transistor is parallel to the circuit board. The flat side must face AWAY from the board. It will rest against the thermal pad you installed in the top cover and must make good contact to transfer heat efficiently. Solder the three leads to Q6.
ELECRAFT 55 Turn the unit face down on a soft surface and measure the resistance between either solder pad for toroid L3 and ground. It should be > 500 ohms. If it is less, you must find the cause before proceeding. If the metal tab 2SC2166 is installed at Q6, the most likely cause will be that the shoulder washer has slipped out or the metal tab on the transistor is touching the case instead of the thermal pad. Install the knob on the encoder shaft.
ELECRAFT 56 Begin by removing the paint from around the holes on the inside of the bottom cover where it will attach to the stand-offs on the circuit board. There are two holes; one at each end of the cover (see Figure 25). Select one battery holder and cut the red wire to 3-1/4” (8.3 cm) in length. Strip 1/4” (6 mm) of insulation off of the end. These are stranded wires. Be careful not to knick or break the strands. Leave the black wire its full, original length.
ELECRAFT Slide the shrink tubing you placed on the red wire over the joint and shrink it in place to insulate the connection. You can shrink it using hot air from a blow dryer or by simply placing your soldering iron very close to the tubing and allowing its radiant heat to shrink it. If you place the barrel of a hot soldering iron (the part just behind the tip) where it almost touches the tubing and parallel to it, the tubing should begin to shrink in about 30 seconds.
ELECRAFT 58 Alignment and Test - Part III Make sure the KX1 is turned off. Connect a 12 to 14-V, 1-amp power supply (or battery) to J1. Make sure trimmer R4 is fully counter-clockwise (drive level). Connect an antenna that is adequate for receiver testing. Plug in a pair of stereo headphones or a speaker at J2. Turn on the KX1. If the display doesn’t appear, turn the KX1 off and disconnect the power supply. Check resistance from the tab of Q6 to ground and from pin 1 of the MCU (U1) to ground.
ELECRAFT i TUNE mode (key-down) is activated by pressing the M E N U and B AN D switches together. Tapping any switch or the keyer paddle will cancel TUNE. During TUNE, the display will show tun. (If the KXAT1 ATU option is installed, the display will instead show both power output in watts and SWR. Refer to the KXAT1 manual for details.) 59 40-Meter Transmit Test Switch to 40 meters (7 MHz). Set the VFO to about 7100 kHz. Put the KX1 into TUNE mode by holding M E N U + B AN D .
ELECRAFT 60 Final Assembly Be sure that you removed the paint from around the bottom cover holes (see Figure 25). Three self-adhesive feet are supplied for the bottom cover. Three feet provide excellent stability on uneven surfaces. Position the feet on the bottom as shown in Figure 27. Place the serial number label inside the top cover as shown in Figure 28. Note: The label is placed on the inside to protect it during field operation.
ELECRAFT Components on the bottom of the board must have an overall height of no more than about 1/8” (3 mm) above the PC board in the area shown below (See Figure 29 ). Fold down or re-solder components if necessary. Also trim any long component leads which were not trimmed earlier. 61 i When you install the bottom cover in the next step, be sure not to pinch the battery cable under the nearby long standoff. Fit the bottom cover in place and secure it with the two 4-40 black knurled thumbscrews.
ELECRAFT 62 Operation This section covers all KX1 connectors, controls, and operating features. For a one-page Quick Reference, see Appendix G. External Power Supply Internal Battery You can connect any 7-14 V DC power supply or battery to J1, although you should use the minimum recommended voltage (8 V) when possible. The KX1 will run from whichever is higher in voltage, the internal battery or the external supply. Transmit current drain will be 300-700 mA, depending on the supply voltage.
ELECRAFT Controls and Display Power Switch Set POWER ON to turn on the KX1. If the LED display is too dim, hold M E N U , B AN D , or R I T at power-up. This selects maximum LED brightness and also turns on audible CW switch feedback at 10, 20, or 30 WPM respectively (see page 69). Lamp Switch Set LAMP ON to turn on the lamp at the front-left edge of the KX1. The lamp can be used to illuminate a log book placed in front of the KX1, or as a flashlight. In an emergency it can be used for visible signaling.
ELECRAFT 64 Pushbutton Switch Functions Switch Combinations There are three small pushbutton switches below the display. A fourth pushbutton switch is built into the VFO knob. MENU a switch to access its upper function (white label); H O L D a switch for 1/2 second to access its lower function (yellow label). Some switches can be held in combination as described at right.
ELECRAFT 65 Menu Functions To access the menu, tap M E N U . You can then scroll through menu entries by rotating the VFO knob (see list below). Hold E D I T to display a menu entry's parameter, then change the parameter using the VFO knob. (Note: PLY and RCL behave differently: there is no need to enter edit mode to use them. See table for details.) Tap M E N U to return to scrolling. Another tap of M E N U will return you to normal operation.
ELECRAFT 66 Advanced Operating Features Receive Mode Selection (CW, LSB, USB) Recording and Playing CW Messages The KX1 provides three receive modes: CW (nor or "normal"), LSB, and USB. Hold M E N U + R I T to select the desired mode. The KX1 provides two message memories of 48 bytes each. CW messages can only be recorded using the KX1’s internal keyer. Set INP to PDn or PDr to use the internal keyer.
ELECRAFT 67 Scanning: Audible CW Feedback on Switch Press To set up scanning, use the STO menu function to save scan start/end points in frequency memories 1 and 2 (for each band). Now, whenever RIT is off, you can activate scanning by holding CLR for two seconds. Scanning is “live” (not muted). It can be stopped by tapping a switch, turning the VFO, or transmitting. If the VFO is set for 10 or 100 Hz steps, scanning proceeds at 100 Hz per step.
ELECRAFT 68 tone, or low/high tone (for 10 Hz, 100 Hz, and 1 or 5 kHz VFO steps, respectively). Frequency Announce mode is turned on in the same was as S-meter mode (hold the DISP switch combination, B AN D + R I T ). When you select announce mode, AF (for announce frequency) will be displayed, and the letter A will be sent in CW. Holding the DISP switch combination again will switch to battery display mode (B) and back to normal mode (N).
ELECRAFT beat (0 Hz audio). If it's a voice signal, tune for most naturalsounding audio. Then exit the menu. Checking the Firmware Revision Hold any switch on power-up to display the revision (e.g. 1.01). Note: Checking the firmware revision by holding M E N U , B AN D , or R I T on power-up also sets the LED to high brightness and enables CW feedback on switch press (at 10, 20, and 30 WPM respectively).
ELECRAFT 70 QRP Operating Tips SWL (Shortwave Listening) Tips Antennas: When you're using low power, a good antenna and ground system can make a big difference. There are many references on antennas available, including the ARRL Antenna Handbook. Tuning Range: The KX1 can tune a wide range on each band: QRP Frequencies: Low-power enthusiasts can be found at certain "watering hole" frequencies on each band, listed below (kHz). An asterisk (*) indicates European or alternative QRP frequencies.
ELECRAFT 71 KX1 Options 30-Meter Module (KXB30) Automatic Antenna Tuner (KXAT1) The KXB30 adds 30 meter coverage to the KX1, and also greatly increases receive sensitivity in the 5.9-6.4 MHz SWL segment (with 40 m selected). 30 meters is an excellent band for day and night operation and is popular with QRPers. Being a WARC band, it is offlimits for contests, and is thus a haven for those not interested in contest operation. WWV or WWVH provide universal coordinated time announcements at 10.
72 ELECRAFT Circuit Details While reading this section, refer to the Block Diagram (Appendix C) and schematics (Appendix B). Receiver: The receiver is a single-conversion superhet, using downconversion to a low intermediate frequency (I.F.) of about 4.915 MHz. Down-conversion minimizes complexity and receive-chain noise, while the low I.F. allows adequate CW selectivity with a variablepassband, 3-pole crystal filter.
ELECRAFT A1 Appendix A - KX1 Parts List i Many parts are static-sensitive, including parts pre-mounted on the circuit board. Wear a grounded wrist strap or ground yourself frequently while handling. Do not handle more than necessary. Do not remove parts with leads in black foam from the foam until they are installed.
ELECRAFT Photo A2 Reference Designator Description Quan. Part No. C26 Capacitor, 120 pF disc (121) 1 E530041 C19, C44 Capacitor, .
ELECRAFT A3 Photo Reference Designator Description Quan. Part No. J1 Conn., DC barrel 1 E620026 MISC Mating connector for J1 1 E620032 J2 Conn., BNC, R.A. PCB mount, no bushing 1 E620075 J3 Conn., 1/8" stereo jack 1 E620027 MISC Miniature three-circuit plug that mates with J3 1 E620033 J4 Conn., 1/8" stereo jack with switch 1 E620028 J5 Conn., 2-pin female housing, 0.
ELECRAFT Photo i Do not mix these with resistors. Keep them in their own envelope until installed. A4 Reference Designator Description Quan. Part No. MISC Crimp pins for J5, package of 2 2 E620022 J6 Conn., 5-pin female, 0.1" spacing 1 E620051 J7 Conn., 3-pin female, 0.1" spacing 1 E620009 J8 Conn., 2-pin female, 0.
ELECRAFT A5 Photo Reference Designator L5 L8 L9 L10 Description mini (larger size) RF choke, 5.6 µH (grn-blu-gold) micro (smaller size) RF choke, 18 µH (brn-gry-blk) micro (smaller size) RF choke, 100 µH (brn-blk-brn) micro (smaller size) or mini (larger size) RF choke, 33 µH (org-org-blk) Note: When color coded, either or both orange bands may appear to be brown. Quan. Part No. 1 E690037 1 E690040 1 E690013 1 E690041 P1 Connector, 2-pin male with locking ramp, 0.
ELECRAFT Photo A6 Reference Designator Description Quan. Part No. R4 Pot, 100 ohm trimmer 1 E520008 R18 R15 R13,R24,R29,R32 R8,R12 R5 R21 R19, R28 R16,R17,R20,R31 R23 R9,R22 R6,R7 Resistor, 3.3M, 1/4 watt, 5% (org-org-grn) Resistor, 1M, 1/4 watt, 5% (brn-blk-grn) Resistor, 22K, 1/4 watt, 5% (red-red-org) Resistor, 6.8K, 1/4 watt, 5% (blu-gry-red) Resistor, 4.7K, 1/4 watt, 5% (yel-vio-red) Resistor, 2.7K, 1/4 watt, 5% (red-vio-red) Resistor, 1.
ELECRAFT A7 Photo i Reference Designator Description Quan. Part No. S1,S2 Slide Switch, SPDT, PCB mount, 0.5A @ 50V 2 E640015 S3,S4,S5 Momentary contact. switch, 6mm 3 E640016 MISC Keycap, square, blue, 6 mm 3 E640017 U1 IC, MCU, KX1, PIC16F876A (E600075) 1 E610017 U2 IC, DDS, AD9834, SMD 1 E600076 U3 IC, TC4427, dual driver 1 E600077 U4 IC, LM386N-1, AF amp 1 E600022 Handle with care – ESD Sensitive. Pre-installed on board i Handle with care – ESD Sensitive.
ELECRAFT Photo Pre-installed on board i A8 Reference Designator Description Quan. Part No. U5,U6 IC, NE602 or NE612 mixer 2 E600006 U7 IC, TPS76427, 2.7V reg, 5-PIN, SMD 1 E600078 IC, 78L05, 5-V regulator 1 E600029 U9 IC, 77L06, Low dropout 6-V regulator 1 E600079 X2-X5 Crystals, 4.9136 MHz, matched set of 4 (using p/n E660000) 4 E850162 X1 Crystal, 3.
ELECRAFT A9 Photo Reference Designator Description Quan. Part No. MISC Battery holder, 3 AA cells 2 E980071 HDWR Screw, 2-56 x 1/8" Panhead Phillips, black (2 spares) 6 E700084 HDWR Standoff, 4-40 x 5/16" long, 3/16" dia., hex, Male-Female 2 E700083 HDWR Standoff, 4-40 x 3/16" long, 3/16" dia., hex, 1 E700068 HDWR Standoff, 4-40 x 3/4" long, 3/16" dia.
ELECRAFT Photo A10 Reference Designator Description Quan. Part No. HDWR Screw, 4-40 x 3/16" pan-head Phillips, black 1 E700015 MISC Rubber foot, self-adhesive 3 E700024 KX1 top cover 1 E100172 MISC KX1 bottom cover 1 E100173 MISC Wire, #26 red enamel MISC Wire, #26 green enamel MISC Knob, 1.15" dia. 1 E980072 MISC Red plastic filter w/two adhesive strips (Packaged with serial number label and thermal pad in a small envelope).
ELECRAFT A11 Photo i Reference Designator Description Quan. Part No. MISC Large Allen wrench, MSC 05471057 5/64” 1 E980004 MISC Sandpaper 1 E850090 MISC KX1 PCB w/pre-mounted parts (U2, U7, Z2); Empty PCB is Part No. E100174 1 E850163 MISC Thermal pad (Normally shipped in the same envelope with the Serial Number label). 1 E700002 MISC Heat-shrink tubing MISC Serial number label Handle with care – ESD Sensitive. 6” (15.
100K 6 RP5 5 8 7 11 6 1 16 1 4 13 4 2 15 16 7 10 7 3 14 3 DIG1 RP3 10K B C 7 13 COLON C12 0.1 VBATT MCLR 1 VFWD/DATA 9 D E 5 DIG2 VBATT G RP3 10K DP 5 DS1 Common-Cathode RA1 RB5 RA2 RB4 RA4 RB2 VSMTR RA5 RB1 VSS RB0 OSC1 VDD OSC2 VSS R13 2 2 K RC0 RC7 R12 6.8K RC1 RC6 C24 27 B 10 2 nc 2 3 Z1 (ENC) 6V RC2 /FSYNC C55 .01 SCK ** 1 RF Gain 2 K1B C27 150 C56 68 CC 50 6 C15 .01 7 U6 R19 1.
LOW-PASS FILTER DDS VFO (U2) BUFFER (Q1) DRIVER (Q4, Q5) POWER AMP (Q6) LOWPASS FILTER WithVFO = 7000.00 kHz and RX Mode = Normal (CW): Fdds, RX = 11913.6 kHz BANDPASS FILTER Fdds, TX = 7000.00 kHz T-R (Q7) AGC (Q9) RCV MIXER U6) MCU (U1) CRYSTAL FILTER PROD. DETECTOR (U5) A.F. AMP (U4) 4.9136 MHz DISPLAY AND CONTROLS BFO 4.913 MHz KEY Common Transmit Receive Appendix C KX1 BLOCK DIAGRAM W. Burdick/E. Swartz Rev.
Appendix D. KX1 Assembly Photographs Assembled PC board, top view NOTE: The power transistor near the center at the top edge may have a black plastic or shiny metal tab.
Appendix E - Troubleshooting KX1 TOP COVER REMOVAL: (1) Remove the three flat-head screws that hold the PCB to the top cover. (2) remove the VFO knob. (3) Flex the front edge of the top cover outward slightly while pulling upward gently on the key jack. The key jack should pop out of its hole. (3) Lift out the PCB. (!) NOTE: If you need to transmit with the top cover removed, Q6 will not have a heatsink. Turn the power control (R4) fully counter-clockwise to limit power to 0.5 watt or less.
03 No audio 05 Current drain is excessive on receive 06 Supply voltage drops when KX1 is on 07 Error in actual vs. displayed frequency 08 Freq.
65 AF amplifier not working VFO (40-59) Problem 40 General VFO (DDS) problem; frequency jumps or drifts 41 Can't tune VFO (or RIT offset) 42 No DDS output Troubleshooting Steps Note: A small amount of DDS drift may occur due to aging of components and heating/cooling of the cabinet Check 14 MHz LPF components (L4, L5, C50-C52) and buffer (Q1, R31) Make sure supply voltage is above 6.5V Check values of R8, R6, R7, RP4, RP3 Check 5V and 2.
an incorrect LPF component value Check relays (25) Examine T1, L3, L1, and L2 for poorlystripped leads Check T1 for backward windings Check all DC voltages in the transmitter (Q1, Q4, Q5, Q6) Signal-trace through the transmitter to find where signal is lost (using an RF probe) Check for any components getting hot 88 Power output fluctuates 90 Output power drops to zero suddenly 92 Current drain too high on transmit 95 Keyer Problem E-4 If you stay in key-down (
DC Voltage Table – Integrated Circuits NOTES: Measurements were made with a 50-ohm dummy load connected and a supply voltage of 13 V. The 30- meter option was installed (KXB30) and the ATU was removed (KXAT1). 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. Shaded areas show transmit-mode measurements (using TUNE). Ref.
DC Voltage Table – Transistors and Diodes NOTES: Measurements were made with a 50-ohm dummy load connected and a supply voltage of 13 V. The 30- meter option was installed (KXB30) and the ATU was removed (KXAT1). 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. Shaded areas show transmit-mode measurements (using TUNE). Ref.
Appendix F Parts Placement Drawing (Top) (Includes KXPD1, KXB30, and KXAT1 boards) 6 D2 C42 C35 Q6 C34 C43 RP3 RP4 + C51 Q1 1 DS1 CC R2 U3 C20 C1 Q2 C13 C U1 X1 - + D1 C25 C5 FLAT SIDE R13 S1 C10 L10 C33 C4 L8 C11 U5 602 S2 + C18 C2 D4 C55 G KXPD1 REV B KXPD1 REV B 2003 ELECRAFT 2003 ELECRAFT J4 R3 Q9 C8 U9 L9 C24 Q3 D C32 1 S D5 R12 C17 C19 C23 G D B S E (SOCKET) 386 Q8 R19 4427 + U4 C16 C12 R1 L6 602 U8 S5 S4 CB L7 RP5 RP1 S3 D2
Appendix F Parts Placement Drawing (Bottom) (Includes KXPD1, KXB30, and KXAT1 boards) C9 R4 R3 KXAT1 ATU REV B C1 C2 FOOT 2003 ELECRAFT NULL C10 R2 C3 R1 REFL 3 + R15 X2 C7 X3 C15 C C3 30A C9 C14 R18 R25 R16 X5 R5 G X4 C1 C5 L2 L1 C2 C4 D2 L3 R5 R4 R17 R22 J3 C3 5 D R29 R20 D1 J6 R23 P1+ G 30B + 1 20B G R14 R10 R27 40 J1 R8 C39 R26 R28 A L4 L5 20A C31 C30 R6 1 R30 K1 R21 4 D7 L3 B K2 2 1 J2 R7 R24 L1 J7 L2 J8 T1 R4 FWD
BAND/SPEED Tap once to show band, twice (quickly) to change bands. Hold to set keyer speed with VFO knob ELECRAFT KX1 QUICK REFERENCE 12V S1 3 5 ANT. 7 9 + RX TX RF 1 TUNE (key-down) : MENU Hold MENU + BAND; tap any switch after power is displayed 2 RIT 0.5 2.0 2 SPEED EDIT Tap for 10/100 Hz, hold for 1 kHz (5 kHz in LSB/USB receive modes) 1.
