Post your Silicon Chip/Jaycar kit questions here!

Can anyone help,

I bought the silicon chip manage theremin, bu it i'm pretty new tot he elctronics world. I managed to finally assemble the theremin and then progressed to the instructions for setting it up, but i am not getting any results from the theremin.

I applied power with a 9v DC (400mA) adaptor and checked for the 'nominal' 6v between the casing of T1-T4 and pin 8 of IC2 but there is not a flicker on the voltmeter; Pin 1 and 2 register about 5 volts and pin 4 and 6 about 3.

So I checked;

every connection = ok
took out IC1 and checked it = ok
checked current at adaptor = ok
checked soldering = seems ok ( there is a slight solder bridge underneath between pin 4-6 of IC2, but these are joined on PCB anyway!)

The speaker is hissing and there is a little interference when i take voltage readings so this inidicates it is responding.

Do you think the adaptor is ok despite it being 400ma?
There is current there but im not getting the desird output. I know its a lot to take in but did anyown have similar problems or could give me some advice?

Thanks,

a worried K-dawg

HI,
I'am french so excuse me for langage.

I'am buiding the Jaycar theremin too.
YOu have no 6 volt on your measures because you have probably a 5 volt regulator, (78l05 instead of 78l06).
I think there no problems on your circuit but check the layout many times and wires too.

Also put away metallic objet from you theremin, it will false all the setup.

It's normal that you have a pitch sound or another sound when you read measure.

you have to set the theremin, tape "silicon theremin" in google and go to the first link
It's all explicated.

Just a quick note to let you all know I've added this theremin to our gallery:

http://www.thereminworld.com/theremins.asp?m=21&t=23

ok jason but to have the full page of the Silicon Chip Magazine Theremin Article I have to tape silicon theremin on googgle and I click on the first link.
It's strange but when I do that, The page is full with the schematic etc..
If I click on yout link "Silicon Chip Magazine Theremin Article" the page is not full

Interesting. From my link, there's a link at the bottom of the page that says "click here for online access to the rest of this article". It looks like they want you to pay for access. The link from the Google search and my link are identical... not sure why one works and the other doesn't.

On the mods' page:
http://www.thereminworld.com/silicon_chip_theremin_modifications.html

THere's a mod whcich consist to add a enamelled copper wire, I don't understand how to do that.

Can you help me to add this mod?

just an other thing:

It's strange
When the speaker's pot is off, The theremin sound's good but when I turn right the speaker's pot there are king of chooping on the sound, the sound is not continue.

Do you know where Could this problem comes from?

FORGET THE LAST POST: I FIND, THE 9VOLT BATTERY WAS DEAD, OOPS
Iam SORRY

Is there someone who arrive to remove the buzz on the sound?
In fact when the volume is low, the sound is pure but when the voulme is higher the buzz begin to arrive.

Mathflan,

send me your email address and I'll send you a photo of how to attach the two "L" shaped wire

Abdul

abdul.nathekar@blueyonder.co.uk