Vanishing Point Sequencer Help

[Michael Allen]

I put it together and fired it up and it didn't work. The first LED stayed lit and the circuit didn't sequence. It would flash but the speed pot had no effect. Then i realized I was using a CD4013? instead of CD4093. I went and bought an NTE4093 and guess what!?! It was a repackaged Texas Instrument CD4093! Do you believe that??

So I put that in and now the clock photocoupler works, but the LED no longer flashes, and the first LED is still the only one lit. Speed pot has no effect, and it doesn't matter whether it's in Random or Sequence mode.

As it's wired up now, I've got a 100pf cap for the random circuit instead of .01uF and a 22k for the 10k-100k. The 10uF-100uF cap is a 68uF.

Any ideas ? I really have no experience with these type of circuits, so I'm in the dark.

Thanks

[The Tone God]

Are you using a CD4017 ? Its easier to debug the sequencer mode so start with that. You can also remove the cap between the sequencer clock and the pulse shortner (0.01uf) to be sure the clock is isolated. You can try to drive an LED with the clock output, when not connected to the 4017, to make sure its pulsing. Check your reset pin connection on the 4017 as well. High is reset and low/open is active.

Are you using the circuit board or have you bread board this ? I was going to etch the 4093 board I posted and a newly laid out 40106 based board either tonight or tommorow to confirm things.

Andrew

[Michael Allen]

I threw together my own layout to minimize space. here's what it looks like right now. I realized afterward that the extra pads for the 6/8 stages are on the wrong pins on the 4017....

http://img.photobucket.com/albums/v368/soma_hero/VanishPoint_Lay_New_pcb.png

I'll try your suggestions right now.

[Michael Allen]

Ok, works now. In random and sequence modes. Speed works good, and so does 6/8/10 switch.

Problem is the pot value. There is only a limited travel from about 2/3 until full turn. Even when the Pot is full counter, the LED does not fully turn off. Is there a way to adjust this without changing the pots? How about the 1k resistor from the final LED to ground?

As it is, it's kind of crappy with the wah sound because the LEDs aren't working well to change the filter.... i'll see what we can do i suppose...

[The Tone God]

Problem is the pot value. There is only a limited travel from about 2/3 until full turn. Even when the Pot is full counter, the LED does not fully turn off. Is there a way to adjust this without changing the pots? How about the 1k resistor from the final LED to ground?

Good to hear that its working. 1K can be adjusted and/or the 10uF cap. Both are apart of the clock circuit. It sounds like you might have a pot with a different taper though. Meassure your pot to make sure.

How is the random mode ?

As it is, it's kind of crappy with the wah sound because the LEDs aren't working well to change the filter.... i'll see what we can do i suppose...

Thats a function of what ever wha circuit you used. As long as there is no ticking getting into the audio the rest lies on the wha circuit you chose. I was going to do a layout of a wha board to go with the VP based on the Morely power wha. I'll see how that sounds/works.

Andrew

[Michael Allen]

you know!! They are audio pots! They were the only type digikey had. I'll reverse them and it should allow me to control the part that acutally matters right?.....

The random is pretty quirky right now, so I'll adjust the resistor value. right now it's 22k, I'll try 100k first.

I used a Morley PWA also...

[The Tone God]

you know!! They are audio pots! They were the only type digikey had. I'll reverse them and it should allow me to control the part that acutally matters right?.....

Yes you can reverse them. They are being used just as varible series resistors. See if you like the range. You can throw some tapering resistors to tweak the range if needed.

The random is pretty quirky right now, so I'll adjust the resistor value. right now it's 22k, I'll try 100k first.

Ok. My concern is that the optocoupler is changing the frequency enough. I'll check it out tommorow when I build mine.

I used a Morley PWA also...

Hmm...I'll give mine a shot. Some part values may need tweaking.

Andrew

[Michael Allen]

Alright, reversed the pots and it sounds much better! I rewired some stuff and now there is much less clock in the signal.

But when using distortion there is mondo clock signal being amplified. Andrew do you have issues with clock signal too? I don't know if it can be avoided, but I'd like to fix it....

This is rocking.

[The Tone God]

Alright, reversed the pots and it sounds much better! I rewired some stuff and now there is much less clock in the signal.

Great to hear. :!:

But when using distortion there is mondo clock signal being amplified. Andrew do you have issues with clock signal too? I don't know if it can be avoided, but I'd like to fix it....

When I breadboarded the VP I didn't have any clock noise but mind I use pretty big breadboards. I'm going to etch a couple VPs tommorow. I'll breadboard the PWA, connect it up, and see how it goes. I'll report my findings when I'm done.

This is rocking.

Andrew