Alternative Parts Table and Assembly Procedure

Updated February 5, 2020

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Parts Table

If you have a populated printed circuit board, then the following additional items will be required to construct the theremin:

Notes:

1. These items are included in Harrison Instruments item number 99999-5977-006. The antenna plate, without the other parts, is also available as item number 99999-5977-005.

2. Approximately 4' of hook-up wire required.

Assembly Procedure

1. Drill eleven holes in the top part of the enclosure as indicated in the Enclosure drawing. Remove metal burrs from the holes using a center reamer. Using steel wool, remove sharp edges from both pieces of the enclosure. CAUTION:  Keep the steel wool away from electronic components, and thoroughly remove any remnants from the workpiece promptly.
   
   
2. Cut the RV1 potentiometer shaft to a length of 3/8 inches.
   
   

3. Solder two 4" lengths of hook-up wire to the potentiometer, RV1, as shown in the Wire Locations drawing. Note that one of the wires connects to both the slider terminal and the counterclockwise terminal of the potentiometer. Mark the free ends of the wires with tape: Mark the wire connected to the slider/counterclockwise terminals "1," and the wire connecting to the clockwise terminal "2." Twist the two wires together for a length of 1.25 inches, being careful not to break the soldered connections.
   
   

4. Solder two 4" lengths of wire to the output jack, J2, as shown in the Wire Locations drawing. Identify each wire with tape: Mark the wire connected to the tip terminal of the jack "3" and the wire connecting to the sleeve terminal "4." Verify that the tip and sleeve terminals are correctly identified with a continuity tester or ohm meter. The sleeve terminal should have continuity (0 ohms) to the jack's threaded bushing. Twist the two wires together for a length of 2.5 inches, being careful not to break the soldered connections.
   
   

5. Solder two 4" lengths of wire to the switch, S1, as shown in the Wire Locations drawing. Identify each wire with tape: Mark the wire connected to the center terminal of the switch "5" and the wire connecting to the end terminal "6." Twist the two wires together for a length of 1 inch, being careful not to break the soldered connections.
   
   

6. Twist the battery connector wires together for a length of 1.5 inches. The black wire corresponds to the negative terminal, and the red wire corresponds to the positive terminal.
   
   

7. Solder a 3" length of hook-up wire to the antenna jack, J1.
   
   

8. Install the output jack, potentiometer, switch, antenna jack, and battery holder in the enclosure as shown in the Assembly drawing, details "A" through "E." Orient the switch, S1, so that the unused end terminal is located toward the middle of the enclosure. Note that the washers and nuts for the output jack, potentiometer, switch, and antenna jack are supplied with these items.
   
   

9. Refer to the Assembly drawing, detail "F." Install the four 4-40 x 1 1/2"-long threaded standoffs on the printed wiring side of the board. Install the circuit board in the enclosure. Orient the board so that solder pads 1 through 8 are adjacent to the potentiometer and switch.
   
   

10. Insert the wires from the potentiometer, output jack, switch, battery connector, and antenna jack through their respective strain-relief holes in the printed circuit board. The wires enter the strain-relief holes from the side of the board with no components.
    
    

11. Trim the wires so they they extend about 1/2" past the holes. Strip 1/16" of insulation from each wire, and solder them to their respective pads, marked 1 through 9, in the Wire Locations drawing. Be sure that the battery connector's red wire goes to pad 7, and that its black wire goes to pad 8. The wire connecting the antenna jack, J1, to terminal 9 should be kept short, with only a slight amount of slack. The wires connected to the output jack, J2, should be routed away from the circuit board.
    
    

12. Attach the knob to the potentiometer so that the knob's index line corresponds to the potentiometer's shaft position; the line should point to the 12 o'clock position when the potentiometer is centered.
    
    

13. Assemble the antenna as shown in the Antenna Assembly drawing. If you purchased the parts separately, banana plug P1's screw and solder lug may be discarded, and the threaded rod should be trimmed to a length of 6".
    
    

14. Install a 9-volt battery, B1, in the holder and attach the battery connector. Refer to the Calibration Procedure to adjust the theremin.
    
    

Text, drawings, and photographs ©2001, 2012, 2014, 2020 by Arthur Harrison