102 Minimum Theremin
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(Back to "Assembly Instructions")
If your 102 Minimum Theremin doesn't work, first follow these basic
Make sure that the battery is fresh, and that the red lead of the battery
connector is soldered to the "9V BAT+" point and the black lead to the "9V
BAT-" point on the printed circuit board (PCB).
Make sure you're using the antenna assembly supplied with the kit, or
its equivalent, and that the antenna plug is firmly inserted into the antenna
jack. Make sure that the wire between the antenna jack and the "ANT" pad
on the PCB isn't pinched by mounting hardware, and that the wire is not
excessively long. The wire length should be just enough to go between the
jack and the board, plus a little slack. If you have provided your own metal
enclosure, be sure that the wire between the antenna jack and the PCB isn't
pressed against a metal surface.
Make sure that the "BIAS ADJ" potentiometer (smaller of the two screw-adjusted parts) and the "ZERO CAL" potentiometer (larger of the two screw-adjusted parts)
on the PCB are adjusted as described in the "Calibration Instructions."
If you are troubleshooting the complete kit (product 101-KIT), carefully
check that all the wires between the PCB and the off board components are
connected between the correct points and soldered properly. Make sure that
adjacent lugs on the potentiometers, OUTPUT jack, and POWER switch are not
bent in a way that would cause them to short-circuit, and that they are free
from excessive solder that may "bridge" between them. Make sure the wires
to the output jack are not reversed. Make sure that the ON-OFF switch is
properly connected. One of the wires to the ON-OFF switch should go to to
its center terminal. Make sure that the wires that connect the SPEAKER terminals
to its paper cone haven't been broken.
If you are troubleshooting just the PCB assembly, make sure that your
user-supplied amplifier-speaker system is working correctly. Check for a
faulty connecting cord between the OUTPUT jack and the audio amplifier or
a problem with the amplifier, especially if a 60 or 120 Hertz "hum" is evident.
If you have a second amplifier and connecting cord available, we recommend
that you try them for comparison.
If your theremin functions, but has poor fidelity, the cause may be interference from a nearby source such as an LED or fluorescent lamp, computer monitor, or appliance. You can determine if the problem is being caused by interference by moving your theremin to another location, away from electrical devices, and noting if there is an improvement.
Next, look at the circuit board:
|Almost all problems with the 102 Minimum Theremin result from improper soldering.|
If you still experience problems, please contact firstname.lastname@example.org for assistance.
|Text, images, and format ©2013 by Harrison Instruments,
Incorporated. No part of this page may be reproduced without express written
consent of the copyright holder.
The 102 Minimum Theremin design is used by licensed agreement with its owner. Specifications may change without notice.
The purchase of these products from Harrison Instruments or a third
party does not convey a license to the buyer.