Theremax; No Output, help wanted!

Looks like I am back to the drawing board..... =\

I recently replaced L3 and L4, hoping for the solution, but alas, I had the same result. It appears that my volume control is not working in any way.

Some "symptoms" are, when I place the jumper from D1 to R83, third lug, I get a pitch tone, but it is very low volume-wise and I need my amp to be turned up all they way. Then when I take it off, nothing is different, same tone, same volume...

Some progress would be nice... I will contact PAiA, but any further information (I know, I know... I've gotten a ton of information, but believe me, I've tried everything I could) would be greatly appreciated as always.

Thanks again!

Eric,

As I recall, you said that the tone control is affecting the sound.

Verify this... at the leftmost setting you should here a mellow tone and at the right a bright tone.

If this is correct, then the problem is most likely beyond the tap (center) lead on the tone control (the sound mixing is primitive here... one side of the pot has the sine wave tone and the other has the derived pulse wave from the comparator -- the wiper of the pot determines the mix between the two.

If you do not get a tone on the right side of the tone control pot, then the problem is a weak signal from the detector circuit. As I mentioned, if you do hear a bright tone, then the signal loss is occuring in the amplifier block.

Okay, I am no Theremin genius, as you can tell, so if by "tone control" you mean turning the Pitch Trim, left or right, then yes, on the leftmost position I get a mellow tone and rightmost I get a bright (high-pitched?) tone. If I have misunderstood your directions I apologize, I'm not yet familiar with Theremin terms/slang (if you even used any) so forgive my ignorance.

So does that verify that my tone control works properly and it is beyond the center lug of the Pitch Trim control?

Eric,

Instead of "Tone" control I should have said the control marked "Timbre". Do you get sound when the Timbre knob is fully to the right (as well as fully to the left)?

Ah,okay.

I tried turning the Timbre, the pitched remained constant, as in it didnt effect anything. However, if it means anything, I did try plugging my mono cord into the stereo port of the Theremax and the output was about 2x louder. It still wasnt as loud as I would believe it to be and none of the volume controls seem to effect anything, but hopefully it will help narrow down on the issue. Tonight I will go over all of the joints and do a continuity check of all of the joints/wires.

Looks as though I may need to conclude this project as over. I have re-soldered literally every joint, checked all polarities, replaced all four oscillators and replaced any component that even looked like something was wrong with it, without any luck. I hate to say it, but I think I have failed with this. I have not given up completely, but until I discover something new, I don’t think I will be troubleshooting anymore.

Thanks so much for all the help kkissinger!