Theremin's pitch antenna works in the other way

Hello, my friend has a theremin moog etherwave, after the power supply was burned and repaired, the pitch antena works in the other way, when my hand moves away the pitch goes up.

it is a calibration problem or may be an component
damaged ?

Thanks

If everything is working ok other than the reverse sensing on the pitch antenna, then the issue appears to be nothing more than a calibration issue.

Try changing the position of your pitch adjustment to see if you can achieve the correct sensing for the pitch antenna.

If that doesn't work, then an adjustment to one of the internal pitch coils should be all that is needed.

-- Kevin

Thank you Kevin, I tested recent and is a worse problem, the signal she is very low and it exists too much noise, I proved fitting to the coils of pitch and volume and nonimprovement, could be a damaged component? everything physically seems well, could be the chip lm13700 in the part of the voltage controller?

If the power supply was damaged due to a power surge or an errant voltage regulator, then it is possible that, besides blowing the power supply, that other components were damaged or weakened. Since the IC's are most subject to this, you might want to consider replacing them and perhaps all will be well. And yes, make sure your power supply is rock solid -- a bad voltage regulator won't help matters, for sure.

You may want to consider replacing the entire circuit board. To persist with your current board may not be worth the aggravation.

Please take my comments as general comments -- I don't have personal experience with your specific model of Theremin. Perhaps others can give you more specific information.

Thanks again, after many tests I obtained a significant improvement in the sound, the frequencies are possible to be listened clearly and loudness, now my problem is with the ground because I continue having noise may be is some suggestion to solve this problem?

Sounds like you are making progress.

One symptom of a grounding issue is when you touch a metal component on your Theremin the pitch jumps. In this case, the Theremin and/or your sound system isn't connected to a good, earth ground. A possible work-around to this situation is to use a conductive wrist strap with a cord and alligator clip. Put the strap on your wrist and attach the alligator clip to a ground point on your Theremin.

A wrist strap probably won't solve a ground-loop situation, though. The solution is to reconfigure all your equipment to eliminate ground loops (which can be a bit of a chore). The other is to use a device, such as the Ebtech Hum eliminator to isolate the Theremin's ground from the rest of your equipment and then use the wrist strap to ground your Theremin to yourself.

Now, if you still can't get rid of the distortion, then there is a source of electrical interference in your area. The way you can locate this is to set your Theremin's pitch control to produce a continuous pitch. Then, while listening to the Theremin, start turning off lights, computer equipment, etc... one at a time. If you turn off something, and the distortion stops, then you have located the problem.

In my studio, one of my external scsi drives was a culprit. Since I don't need to run it most of the time, I just keep it turned off to keep my Theremins "happy".

If you can't eliminate the distortion by turning equipment off, then try playing your Theremin elsewhere to see if the distortion changes or goes away. Try other rooms in your house, or even try it at a friend's house.

I would suggest to just "hang in there"... indeed, I have dealt with all the above problems at one time or another. Some patience and experimentation will lead you to a solution.

Best wishes!

Thank you very much by the advice, I improved the calibration still more and I am almost free of noise, I will prove to eliminate it totally with which you explain to me. Greetings

Buddy, ere's another one for you...