PLEASE HELP: Is my theremin broken??

Hi, I am very new to the world of theremins. I fell in love with the instrument a while back and finally found someone in my area who owns one and was willing to rent it to me. I've been using it for almost a month, and although I don't know much about it, I've certainly been enjoying myself. Yesterday, I brought it to my mom's house to show her what it is and what I've learned. 

Today, I set it up just like normal to practice some more. As I began tuning it by adjusting the pitch knob, something odd happened for the first time. As I brought my hand from the pitch antenna to closer to my body, there was a small chunk of space that wasn't emitting any sound. And instead of the sound getting lower after that space, it just sort of stays at a random pitch if that makes sense? It's as if a few keys are broken on a piano. 

I was extremely careful with it on its only outing with me, and I have done everything exactly the same as I always have. It's not near any interferences, it's set up in the exact same place as it has been. I'm scared that I did something wrong and messed it up for good, and I'm even more scared of possibly having to tell the owner (He knows next to nothing about theremins and wouldn't know how to fix it, either). 

Is there anything I can do? Is it the theremin or could it be the amp? Is it done for? In need of some answers and some comfort. Thank you.

what is the manufacturer/model?

Moog etherwave plus

Does the volume antenna still function correctly?

Is the problem the same regardless of whether you use the line out or the headphone out?

is the theremin properly grounded? Either the theremin itself or the device it’s plugged into needs a proper three-prong ground for it to function properly 

arnber, don't worry too much, it's not broken. 

i think i have the same sensation after zero-beat zone on the negative pitch side. i noticed it on the pitch cv-output when connecting external synths. sounds pretty like sample and hold, random notes  and they can be modulated on pitch and speed. around a sweet spot, you can even pick a random note and hold it, let go and pick another one and so on. funny. not shure what that causes, but i guess: maybe the plus board when converting pitch to cv?

Sorry for no response - the problem went away I believe the next day and to be honest I just wanted to put that scare out of my mind. The renter offered to sell it to me for a good price and I needed some time to get the money together. So I'm just about to buy it from him, and now the same thing is happening. It's gone on for a few days now. Is this normal? Will it go away again? Should I not buy the theremin?

To BBrinkman - it is grounded. The stand is similar to a microphone stand in that the bottom is round instead of three-pronged, but it's sturdy. 

To xtheremin8 - do you have this problem often? How do I avoid it?

Also to BBrinkman, forgot to add - the volume antenna still functions perfectly fine, and I don't have headphones to try out your other suggestion. I have noticed that in that "nothing space" I can hear a TINY super high-pitched feedback-type sound. And compared to the last time this happened, the "nothing space" is much smaller and when I surpass it moving away from the antenna and to my body, I think the pitch gets a little higher as it goes. Almost like it's backwards.

Hi arnber,

these beasties are really quite temperamental and temperature, humidity, position of things around them, your position relative to them and so on all contribute to the setup of them. So all in all, it is highly likely that you will have to set up your instrument every time you want to play it and even every so often as you play it.
It definitely pays to be consistent in your setup so that you will become familliar with note spacing and so on.

The phenomenon you describe (noise--->silence--->reverse noise) is normal.
(see video below)

https://www.youtube.com/watch?v=MJEbIMOfAMg

arnber, FYI i have it only on pitch-cv out. not on the audio output. so this might not be related to your issue at all.  

the high pitches you hear in the zero-beat zone are more likely to be considered as a problem called "birdies". i'm not sure how to get rid of them, but i think a very slight retuning of one of the oscillators could help. or some posts here on t.w. could guide you through.