I put my theremin on top of my refrigerator for a while and I tried to play it the other day and it barely makes a sound. Does anyone know why, or anything I can try to fix it?
The fridge killed my theremin!!!
Posted: 6/9/2009 7:08:50 PM
I need more details for a diagnostic:
Which type of theremin is it?
What does "makes barely a sound" mean? Not enough output volume or a pitch field issue?
Fridges are cold inside but tend to heat outside. So it may be that some oscillators have been detuned by temperature or condensation. Try to move it into a place with normal ambient temperature and let it acclimate for 24 hours before giving it a new try.
Which type of theremin is it?
What does "makes barely a sound" mean? Not enough output volume or a pitch field issue?
Fridges are cold inside but tend to heat outside. So it may be that some oscillators have been detuned by temperature or condensation. Try to move it into a place with normal ambient temperature and let it acclimate for 24 hours before giving it a new try.
Posted: 6/14/2009 6:55:43 AM
Yeah, I let it cool down but it's still the same. I don't know if the fridge had anything to do with it, that's just all I can think of. If I turn up my amplifier really loud, you can hear it working but really quiet. I wonder if the amplifier section in the theremin isn't working. My guitar amp works fine so I know it's not that.
Posted: 6/14/2009 7:25:47 AM
yeah, I've got the Mood etherwave signature series theremin, signed by Bob Moog. It says it's made by Big Briar.
Posted: 6/14/2009 6:32:38 PM
Yeah, I've got a cheap one that I think works and another one that I can't seem to find. What should I check?
Posted: 6/15/2009 5:42:23 PM
First, unscrew the cover (two screws at the front side and two on the back side). Then we'll check the internal power supply. It is symmetrical, that means that there should +12V and -12V vs. ground. I've seen Etherwaves where one of both voltages was missing and which showed exactly this behavior. Locate the 8 auxiliary connector pads at the rear side of the circuit board. The leftmost is ground, so connect the black lead there and check with the red lead against pin 4 for +12V and against pin 5 for -12V (power supply connected and the theremin switched on). If both voltages are present, go to step 2, if one is missing or too low, stop and write here which one.
Step 2: Check the volume circuit
Let the black lead at pin 1 of the aux connector. Connect the red lead to pin 12 of U3, this is the 16 pin integrated circuit. Now, with all cables, metal parts and body parts far away from the volume loop, it should show a slightly positive voltage greater or equal 0V. Then bring a hand close to the volume loop. This should give a reading of about -12V. Then move the hand and check if the voltage reading follows more or less the distance between volume loop and hand.
Let us know what happens and we'll continue.
Step 2: Check the volume circuit
Let the black lead at pin 1 of the aux connector. Connect the red lead to pin 12 of U3, this is the 16 pin integrated circuit. Now, with all cables, metal parts and body parts far away from the volume loop, it should show a slightly positive voltage greater or equal 0V. Then bring a hand close to the volume loop. This should give a reading of about -12V. Then move the hand and check if the voltage reading follows more or less the distance between volume loop and hand.
Let us know what happens and we'll continue.
Posted: 6/16/2009 8:07:27 AM
Cool, I found the ground, the +12 and -12 volt pins but I've only ever used my multimeter to check resistances. This multimeter only has DCv (15, 150, 1000), RX 1K (I think this means resistance right?), 150mA DC, and ACv (15, 150, 1000). Which one should I set it to?
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