Instructions for Assembly Page 1 of 5 1. Find Resistor R1. Remove any tape that may be attached to the leads. Bend the leads as needed to insert Resistor R1 into the printed circuit board in the holes marked for R1. It does not matter which lead goes in which hole. Bend the leads outward so that the resistor cannot fall out of the printed circuit board. A photo of the completed process is shown below. Put a check mark in the box when you are done. Horizontal Mounting (If it fits.) Vertical Mounting (If it will not fit horizontally.) 2. Repeat step1 for R2. 3. Insert R3. (Use same method as in step 1.) 4. Insert R4. Hint: Don t accidentally put one lead through the hole labeled E. The correct hole is just under the 4 in R4 Not Here!
Instructions for Assembly Page 2 of 5 5. Insert C1. 6. Insert C2. 7. Insert C3. Hint: The capacitor goes over top of the symbol, not over the label C3. 8. Insert C4. 9. Insert CT1. Hint: After inserting the part in the board, use a pliers to bend the very short leads outward so the capacitor cannot fall out of the printed circuit board. 10. Insert TR1. Hint: Be sure the flat side faces C4. The left-most lead goes in hole E, the middle lead in hole B, and the right-most lead in hole C. See the photo below. 11. Insert the microphone in holes 2 and 3. The pin that is connected to the metal case of the microphone must be inserted in hole number 3. Be sure the case of the microphone does not touch R4 or a lead from R4. Bottom view of microphone This pin must go in hole 3 Note Connection to metal case 12. Compare your circuit to the photos below. Make sure everything installed so far is in the right place for soldering. (The two photos are of the same circuit board but taken from different angles.)
Instructions for Assembly Page 3 of 5 DO NOT PROCEED UNTIL EVERYONE IN THE ROOM HAS SAFETY GLASSES ON Molten solder can splash like water. If a drop of liquid solder (about 500 degrees F) lands on your skin you will be burned and scarred. If you do not wear safety glasses you could be blinded. Move the soldering iron slowly. Make sure you do not cause a splash. Plug in the soldering iron and let it heat up. Unwrap about six inches of solder. To make good connections while soldering follow these guidelines: A.) Solder bridges must be avoided. They are caused by using too much solder or by dragging the soldering iron away from the connection rather than lifting it. To check for a solder bridge you must first look at the circuit board before soldering a connection to observe were there is copper and were there is not. Afterwards, check to see that all the solder stayed on the copper trace and that none is hanging over a green area. Solder Bridge B.) C.) Begin soldering by touching the solder to the tip of the soldering iron to melt a small drop of solder onto the tip of the iron. It usually takes about 1/8 inches of solder to do that. Then place the wet (with molten solder) tip of the iron against both the lead wire and the circuit board trace with gentle pressure an ounce or two. Let the wet solder on the tip of the iron conduct heat into the trace and lead wire. This will take only a second or two. Add solder between the soldering iron and the lead wire. Apply only enough solder to wet and fill in around the lead wire. Usually only a small amount of solder is needed (about ¼ inch of solder wire). Avoid making a big blob of solder on the connection. Besides looking ugly, it might not connect well (traps rosin and dirt) or it might drool and cause a solder bridge. Solder Soldering Iron Lead Wire Copper Trace Circuit Component Circuit Board D.) A properly soldered connection is shown below. E.) Trim lead wires off after soldering. Use a diagonal wire cutter for the task.
Instructions for Assembly Page 4 of 5 13. Solder all the mounted parts in place. Trim the excess length of the lead wires off as you go. 14. Use one of the longest pieces of trimmed lead wire to make jumper wire J1. Install the jumper in the circuit board (on the tan side) by putting one end through the hole below label L1 and the other through the hole below label R3. Solder both ends (on the green side of the circuit board). On the next page there is a photo showing jumper J1. 15. Use a jeweler s small flat-blade screwdriver to scrape the green coating off the copper around the extra hole shown in the photo below. Do not scrape the copper away, just the green coating. Before scraping After scraping 16. Use a long-nose pliers to bend hooks onto the ends of the wires for the switch. You may also need to use a wire stripper to remove about ¼ inch of insulation. Use the pliers to gently crimp one wire onto a post of the switch. Solder the wire to the switch. Repeat for the other wire. (It does not matter which wire goes to which post.) Wires hooked Red wire crimped Red wire soldered Black wire done too. 17. From the tan side of the board, place the black wire from the battery connector into the hole labeled. On the green side of the board solder the wire in place. 18. From the tan side of the board, place the red wire from the battery connector AND the black wire from the switch in the hole that you scraped clean in step 15. Solder them in place on the green side of the board.
Instructions for Assembly Page 5 of 5 19. From the tan side of the board, place the red wire from the switch in the unlabeled hole closest to the black wire from the battery connector. Solder it in place on the green side of the board. 20. Unwrap the antenna wires. The black wire is not needed. From the tan side of the board place the bare end of the red wire into the hole marked ANT. Solder it in place on the green side of the board. 21. Before attaching a battery, compare your completed wireless microphone to the photos below. If there is a mistake, you may ask one of the lab instructors for help. There are techniques for unsoldering a connection without damaging anything. Note: Jumper J1 goes here. (See step 14.) 22. When you are sure your project is assembled correctly, attach the battery and try it out. 2002 Douglas De Boer and Dordt College