UVICS - Univibe In a Crybaby Shell

[aryk]

Should I change my wiring according to the J and K set up? Or was that supposed to be labeled as D and C?

[R.G.]

OK, from the pics, you're using a GGG board to make 17V from 9.

(1) does that work separate from the UVICS board?


If so, yes, you should move the +17V wire to pad J, the negative side of the 17V supply to pad K, and the two free ends of the pot(s) to pads C and D. The center of the two speed pots goes to pad E.

[aryk]

Aha! We have power and ground now closed! Lamp is pulsing as well. Still no effect... but it's a step closer!   K now what? lol

[R.G.]

There won't be any effect until the light shield goes over the LDRs. If there is no effect after that, let's do "what to do when it doesn't work".

[aryk]

Light shield in place and no change.

[R.G.]

Light shield in place and no change.

Time to start with "what to do when it doesn't work".

[aryk]

Any reference points to see where I can trace the audio signal? Or maybe places where I should have audio?

[R.G.]

You should hear about unity gain audio on the collector and emitter of Q3, 5, 7, 9, and 10.

[aryk]

I have unity at all those places. Would i be able to hear any effect signal anywhere? I know i shouldnt hear it til after the 4th stage of mixing.

[R.G.]

Pads L and M. If it appears there, it's a wiring issue off board.

If it does not, check both ends of R37 and R38, and all three pins of trimmer TR3.

[aryk]

No effect at pads L and M other than a slight vibrato on M. Same thing for the TR3. R38 and 37 are just unity gain.

[R.G.]

No effect at pads L and M other than a slight vibrato on M. Same thing for the TR3. R38 and 37 are just unity gain.

But unity audio level at all points?

[aryk]

Correct. Sorry I'm bad with detail, I always assume people know what I'm talking about lol.

[R.G.]

If that's the case, then it could be:
1. LDRs are not  varying enough in resistance.
2. One or more LDRs (and resistors, etc.) are open in the phase line.
3. The trimmer is way off or open to one side
4. The off-board wiring is not set up right.

Just guessing. You're getting perilously close to needing a scope.

The LFO is running, the phase line passes audio. The vast majority of univibes work when that's done.

[aryk]

I followed the wiring according to the version 3 layout. Checked the trim pots to set all at middle position and am not sure about the LDRs they were from small bear and I can't remember the specs on them. I think they were specialized for these type of circuits though.

[R.G.]

There aren't many things that could be wrong from here.

If I understand you correctly, you're getting audio through the phase line and through the dry path. That's getting mixed in the mixer and getting to the output jack. If that's so, the only thing left is that the phase line isn't shifting, or that the mix is not happening correctly.

Really, it's oscilloscope time. Do you have a scope?

[better - pm me.]

[Brejna]

Hi everyone, I am preparing part order for the son of UVICS and cannot find what is U3 in the pdf.  
Brane

[R.G.]

Congratulations, you've found a secret area.   

U3 is an optional third method of making an LED blink. It's an LED to phototransistor optoisolator.

Is this something you plan to do?

[Brejna]

Is there any reward   
Thanks for fast responce, I attend to build it next month so this was only area that I couldn't understand.
Is there any specific opto or?
Brane

[R.G.]

Is there any reward   
Thanks for fast responce, I attend to build it next month so this was only area that I couldn't understand.
Is there any specific opto or?

Reward? It depends.    First you have to want to have an blinking LED. Then you have to pick that one of the three different ways to do it.

There is an opto I was planning to use, but there are many, many optos with the same pinout. They differ primarily in their speed - which does not matter in this case at all - and in their current transfer ratio (CTR). The CTR is the ratio of current in the phototransistor to current in the LED. For this application, you want it to always be greater than 100% - that is, the current through the LED being driven makes more than amount of current flow in the photo transistor. I'd be tempted to use a photodarlington with big CTR; but then the LED would merely blink on and off, no fading.