Here we go again... Zombie Chorus not chorusing...

[lazerphea]

Hello all!
I had the (bad) idea to tell a friend of mine I will build a zombie chorus for him for his birthday; I already built one, he always loved the tone, so I thought it would be nice to give one to him.
Obviously, something went terribly wrong, and I'm now here begging for your help!
Let's start with the debugging form:

* Project name: Zombie Chorus from Geofex
* Link to the schematic: http://www.geofex.com/PCB_layouts/Layouts/zombie.pdf
* I did my own perfboard layout
* No parts substitution, I just used some 0ohm resistors instead of wire
* Negative ground circuit
* The sound of the guitar passes through the circuit, but there's no chours effect. I can hear the ticks and I can modify their speed with the speed pot, but when I turn the depth pot it doesn't affect anything

Measurements (in parentheses the voltages I measure from the working chorus, with the same battery):
U1:
1 - 7.29 (4.9/5.02)
2 - 6.57 (4.9/5.08)
3 - 3.31 (2.35/3.02)
4 - 0
5 - 5.96 (4.80/4.70)
6 - 6.05 (4.89/5)
7 - 6.05 (4.89/5)
8 - 8.39

U3:
1 - 1.2/5.7 (1.33/7.66)
2 - 5.06 (4.96/5.04)
3 - 3.9/5.6 (3.9/6.3)
4 - 0
5 - 5.06 (4.9/5.06)
6 - 5.36 (2.30)
7 - 4.62/5.9 (3.9/6.2)
8 - 8.40

MN3007:
1 - 8.39 (8.21)
2 - 4.11 (4.09)
3 - 7.28 (4.89)
4 - 0
5 - 0
6 - 4.15 (4.09)
7 - 5.99 (4.78/4.98)
8 - 5.99 (4.78/4.98)

CD4046:
1 - 0
2 - 4.11 (4.08)
3 - 4.15 (4.08)
4 - 4.15 (4.08)
5 - 0
6 - 0.88 (1.04)
7 - 0.87 (1.04)
8 - 0
9 - 4.81/5.46 (4.84/4.96)
10 - 3.96/4.68 (3.50/3.62)
11 - 3.73/4.37 (3.12/3.23)
12 - 6.27 (5.77)
13 - 0
14 - 8.37
15 - 0
16 - 8.37

To me, it seems something's wrong with U1: in my working chorus the measurements I get at the pins vary (I think accordingly tothe triangle ramp generated by U3...?) while in this case they remain constant; there are, however, some other differences in voltages but I assume they are caused by the speed and depth pots not being at the same exact value both in the functioning chorus and the non-functioning one.
Thanks to everyone willing to help me!
Paolo

[Devius]

I built the john hollis easyvibe. That circuit was a bastard as it was one of my first builds. I built it twice but it seemed the only issue I had (which seems to be a recurring theme) Is solder bridges. I took a utility knife and scratched between all the joints. Ta da! Problem solved!

[lazerphea]

Thanks Devius, I'm staring at this monster for hours now, I really don't know what I did wrong... :\

[Perrow]

I got mine working but I used my own layout, I think there's some info in this thread, but beware, even though the thread title says "Zombie Chorus" it's mostly about the Small Clone chorus.

[lazerphea]

Problem solved!
Dude, I want to kick myself in the teeth so bad... I used 4558 instead of TL072 cause I thought nothing would change (in the schematic document it is said "dual opamp", so I thought one or another wouldn't mind...)... I swapped opamps and ta-dah! Sweet chorus!
Now I just want to figure out how to de-tick it...

[lazerphea]

Just to be super-shure: to de-tick it, the idea is to feed pins 2 and 5 of U3 with 4.5V (V+/2), right?

[lazerphea]

Just to be super-shure: to de-tick it, the idea is to feed pins 2 and 5 of U3 with 4.5V (V+/2), right?

Yay! I answer myself: did that and worked like a charm! At very high volume you can still hear the ticks, but I think this is physiological...

[cmdrfun]

Thanks for this... I just built one of these and also used 4558's, and had the exact same issue, except I can't hear ticking. Will swap for TL072's and see if that helps. I thought I had accidentally shorted my input to output or something. :-)

[Mark Hammer]

You want to use a low power chip like tl062, or lm358, or tl022 for the LFO to keep the ticking quiet.

[cmdrfun]

Well, I switched to TL072s and it's not chorusing, although I can hear ticking now.

Here are my voltages.

U1: TL072
U1-1: 5.64
U1-2: 5.64
U1-3: 1.06
U1-4: 0.00
U1-5: 0.97
U1-6: 1.49
U1-7: 1.50
U1-8: 9.38

U2: MN3007
U2-1: 9.36
U2-2: 4.63
U2-3: 5.64
U2-4: 0.00
U2-5: 0.00
U2-6: 4.70
U2-7: 5.51
U2-8: 5.51

U3: TL072
U3-1: 5.66 (fluctuating quite a bit from 5.5-5.7)
U3-2: 5.59
U3-3: 5.80
U3-4: 0.00
U3-5: 5.59
U3-6: 1.56
U3-7: 5.84
U3-8: 9.33

U4: CD4046BE
U4-1: 0.00
U4-2: 4.61
U4-3: 4.68
U4-4: 4.68
U4-5: 0.00
U4-6: 1.08
U4-7: 1.07
U4-8: 0.00
U4-9: 5.48
U4-10: 4.06
U4-11: 4.01
U4-12: 7.54
U4-13: 0.00
U4-14: 9.31
U4-15: 0.00
U4-16: 9.31

Thanks in advance...