Three sections of the receiver are modified for SWL reception.
The first one is the "VFO and Amplifier" Section. The VFO frequencies are changed and the IR devices are replaced by SPST switches. One coupling capacitor to the main tuning capacitor is raised and the capacitor at the 10.545 relay is removed. Small SPST switches are wired to the board to provide VFO switching. Soldering the IR devices on the board is optional.
The Crystal Filters are modified in the "First Mixer, Post-mixer Amplifier, Crystal Filters" Section. Two of the crystals are removed to provide a wider bandwidth for AM reception.
The third section, "BFO and Amplifier, Product Detector and Audio Amplifiers" Section, is built for AM detection by modifying the Product Detector, disconnecting the BFO, and bypassing the audio pre-amplifier.
Soldering the Boards
Also see Soldering Stations and Techniques For the Electroluminescent Receiver Kit for more details.
Please build the kit with SAFETY in mind. Be careful with a hot soldering gun loaded with solder and clipping leads off the boards.
Take your time and don't work on the kit when frustrated with life problems (though there is a possibility working on the kit can be good relaxing therapy).
Use solder that does not leave a large amount of rosin on the board. Using too much rosin will leave the board a dull color. With proper solder, your joints will be a bright silver color when finished.
The best solder to use is silver solder available in a small roll (1.5 oz.) from Radio Shack, part no. 64-013 E. The solder is .022 inch diameter with a 62/36/2 mix. It is labeled "High-Tech Rosin-Core Silver-Bearing Solder" with a red and white label. One roll should solder the receiver.
Regular lead solder that works well is 63/37 alloy sized .032 inch, 1.0mm, or 0.8mm rosin core.
When inserting the parts on the board, do not clip the leads until after they are soldered. Bend the leads at a 45 to 55 degree angle on the bottom side of the PCB to hold the parts on the top side against the PCB. See Soldering Techniques for the ELR.
Double check your soldering by flicking the leads to see if you can get them to "ring". A unsoldered lead will not "ring" and feel loose when touched.
Clip the leads slightly above the solder. Do not cut into the solder.
Point the board away from your eyes when clipping the leads. They fly with considerable force from the board. Best to have the board over a large trash can to prevent them from flying all over the work room.
Another technique is to hold the long leads with your finger when cutting. For shorter pieces, place your finger on top of the leads when cutting; they will fall on top of the board after being cut. A light touch is all that is needed, be careful not to poke or cut your finger.
Before You Start
Please keep in mind that 90% of the active devices in this kit are static sensitive devices.
Protecting Static Sensitive Devices
The highest risk situations are living in a very dry environment (or a day with very low humidity), and wearing rubber sole shoes with carpet on the floor.
If you walk across the floor of your work room and get a static discharge when you touch the door knob to your work room, have a ground lead running across the front of your work table to ground yourself before working on the receiver.
At the very least, have a ground lead handy to give a quick touch when sitting down to work. You will be instructed to touch the ground lead before inserting any static sensitive devices.
Checking Your Soldering Iron
Check the ground on your soldering gun by putting an LED between the tip of the soldering gun (when turned on) and the ground you are using. Polarity does not matter nor do you need a resistor in series with the LED.
If it lights, you do not have your soldering iron grounded properly. If you are not sure, do the test in dim/no light.
If this test blows the LED, you could be in danger of a very nasty shock. Fix this problem before building anything! Two wire electrical systems, with no third ground wire (two prongs only), is the most likely situation where this problem will occur.
The receiver is most susceptible to the above problem after it is built and connected to an antenna that has a proper ground.
The soldering gun will put 120VAC (or 230VAC) on the trace you solder and travel to the ground of your antenna, blowing any active devices connected to the trace.
If you follow the above precautions, there should be no blown devices when building the receiver.
The warnings, cautions, and instructions discussed in this instruction manual cannot cover all possible conditions and situations that may occur. It must be understood by the operator/builder that common sense and caution are factors which cannot be built into this product, but must be supplied by the operator/builder.
Do not have the bottom of the board pointed toward your face while clipping the leads after soldering parts to the board. Some of the leads will take off like rockets and fly all over the room and maybe into your eye.
The best place to clip leads is with the board facing down into a large trash can.
Solder and Your Health
Be sure to wash your hands after every soldering session with the kit.
For the residents of California (and should be noted by everyone):
This product may contain and/or may be used with solder. Solder contains lead which is toxic. Lead is known to the State of California to cause cancer, birth defects, or other reproductive harm.
KEEP SOLDER AWAY FROM CHILDREN!
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