ELECRAFT® K3 HIGH-PERFORMANCE 160 – 6 METER TRANSCEIVER INSTALLING CRYSTAL I.F. FILTERS Rev A, October 15, 2007 Copyright © 2007, Elecraft, Inc.
Contents Introduction............................................................................................................................................... 3 Customer Service and Support............................................................................................................................ 3 Technical Assistance ....................................................................................................................................... 3 Repair / Alignment Service ....
Introduction The K3 transceiver can accommodate up to five high-performance crystal I.F. filters of different bandwidths. This manual covers the installation of additional filters to your transceiver. Only a few basic hand tools are needed (see page 5) to perform the installation. No soldering or wiring is required. Customer Service and Support Technical Assistance You can send e-mail to support@elecraft.com and we will respond quickly - typically the same day Monday through Friday.
Preventing Electrostatic Discharge Damage There is no climate or work location where the components of your K3 are safe from Electrostatic Discharge (ESD) unless you take specific steps to prevent such damage. Many of the components in your K3 can be damaged by static discharges of only a few volts: far too little for you to notice. It is those low-voltage but destructive discharges that easily happen anywhere and under virtually any environmental conditions. ESD damage may not be apparent at first.
• Wear a conductive wrist strap with a series 1-megohm resistor. If you do not have a wrist strap, touch a ground briefly before touching any sensitive parts to discharge your body. Do this frequently while you are working. You can collect a destructive static charge on your body just sitting at the work bench. DO NOT attach a ground directly to yourself as this poses a serious shock hazard. • Use a grounded anti-static mat on your work bench.
Installation Procedure Disconnect power and all cables from your K3. Remove the nine screws to free the top cover as shown in Figure 2. After the front edge of the cover is opened as shown in the figure, set the unit back on its bottom feet and lift the cover gently to reach the speaker wire connector. Unplug the speaker then set the top cover aside in a safe place. 1 2 REMOVE SCREWS HOLDING TOP COVER. PLACE UNIT ON ITS SIDE FEET, THEN TIP FARTHER SO THE TOP COVER SWINGS OPEN FAR ENOUGH TO GRASP.
Look at the filters you already have installed. They are located just behind the front panel shield (see Figure 3 showing two optional 8-pole filters installed). The filters must be installed in descending bandwidth order with the widest bandwidth toward the FL1 position and the narrowest bandwidth toward the FL5 position. You may need to move existing filters in order to preserve this order after installing the new filter(s). The bandwidth is marked on each filter in Hz except for the KFL3B-FM filter.
Turn your K3 upside down and remove the bottom cover panel nearest the front to gain access to the screws that hold the filters in place. To free the bottom cover, remove the seven black pan head screws. Do not loosen the screws holding the feet. Remove the mounting screws and lock washers holding any existing filters that you need to move to maintain the order with the widest bandwidth filter closest to the FL1 position. The screw positions are shown in Figure 4.
Turn the K3 upside down again and install the mounting screws and washers for each filter as shown in Figure 5. CAUTION 1) Use screws no longer than 1/4” (6.4 mm), as specified, measured from the flat surface below the screw head to the end of the threaded shaft. Use your ruler to measure the screws before installing them. Longer screws may extend into the filter unit and destroy it. 2) Do not over-tighten the screws. Too much torque may pull the threaded bushing out of the bottom of the filter module.
With the K3 right side up, plug the speaker wire into P25 on the KIO3 board at the left rear of the K3 as shown in Figure 6. KIO3 BOARD IN BACK LEFT CORNER OF CHASSIS ORIENT CONNECTOR AS SHOWN TO SPEAKER Figure 6. Connecting Speaker Cable. Position the top cover on the K3. Note that the tab on the back center goes under the rear lip of the K3 rear panel. Secure the top cover with the nine 4-40 3/16” black flat head screws you removed earlier. That completes the installation of your new crystal I.F.
