EHX Small Clone Vero not working

[bluebunny]

Now that I have a working one I can test alongside the non-working one, how should I proceed?

If it were me, I'd take a deep breath and methodically go around measuring voltages in each circuit (concentrating on the active devices at first) until I spotted a difference.

[freshmex18]

It looks to me like the two op-amps are the other way around from the schematic.
I'd expect the schmitt trigger to swing from one rail to the other - that *might* be 0.32 to 7.57, but 1.16 to 2.28 doesn't look much like a rail-to-rail output.

On the other hand, I'd expect the integrator to have a larger output than that too, and biased around a higher point, given the 4V on pins 5 and 6. So I'm not sure. It still doesn't look right, really.

Now that I have a working unit, here are those LM358 values with Lug 3 of Depth pot disconnected


LM358 - IC4

1 Fluctuates from 0.03V to 7.65V at a noticeably slower rate than with the non-working unit
2 2.19
3 Fluctuates 0.35V to 3.58V
4 0
5 4.02
6 4.05
7 Fluctuates 0.87V to 2.28V with rate pot at min; 1.27V to 2.28V with rate pot at max
8 8.89

[freshmex18]

Now that I have a working one I can test alongside the non-working one, how should I proceed?

If it were me, I'd take a deep breath and methodically go around measuring voltages in each circuit (concentrating on the active devices at first) until I spotted a difference.

That's what I figured/was afraid of.  I only have one LM358 so I hope I can find the problem with that removed from both circuits.  Not sure when I am going to make another order

[duck_arse]

I'd be inclined to take a photo of both boards, then load them into layers in an image program, align them as best I could, and see if I could see any difference. transparent layers and all that.

you might also discover Pluto.

[freshmex18]

Took a few days away from pedals for my sanity.  Came back to compare the voltages of the working unit against the non-working one and with the LM358 removed I found that the voltages were off at pins 1,2,and 3 of the the CD4047


Working unit
1 8.37V
2 8.36V
3 8.81V

Non-working unit
1 0.47V
2 1.94V
3 5.3V

Wondered if my batch of 4047s from Amazon was at fault and swapped a few in and there were some voltage changes but not quite right.  Then I swapped out the 150p cap for a new one and bang, the result was a fully functional unit.  So the problem was the 4047 and the 150p together, it seems

So now I have two working units.  I think a friend of mine will be getting a Small Clone for Christmas.

Thank you all for all of your help.  This was a really frustrating build.