Help debugging a tonepad CE-2 Corral chorus

[krankguitarist]

http://www.tonepad.com/getFile.asp?id=101

I just put together a CE-2 clone from the above layout.  I etched my own board for the project.

I fired it up yesterday and got nothing but a buffered signal.  Turning the rate and depth knobs don't really seem to do anything.  While adjusting the trimpot I hear a slight change at one point during the rotation.  The change is a little difficult to describe to be honest, almost like a slight shift.

I've gone over the whole board twice with my soldering iron re-flowing all the solder joints.  I've gone over the back of the board with a magnifying glass and cant find any solder bridges.

I built an audio probe in an attempt to debug this project.  I get a signal at R13, but at C10 it becomes very distorted.

Here are my voltages:

IC1 (4558):
1) 4.53
2) 4.53
3) 4.52
4) 0.0
5) 4.53
6) 4.53
7) 4.53
9.3

IC2 (TL022)
1) 8.59
2) 4.63
3) 0.0
4) 0.0
5) 4.63
6) 7.78
7) 0.63
9.3

IC3 (MN3007)
1) 9.23
2) 4.72
3) 3.82
4) 0.6
5) 0.0
6) 4.69
7) 3.61
3.61

IC4 (MN3101)
1) 9.23
2) 4.69
3) 0.0
4) 4.71
5) 0.26
6) 8.37
7) 2.47
0.61

Q1
E) 3.55
B) 3.97
C) 9.3

Q2
E) 3.82
B) 4.35
C) 9.3

Q3
E) 3.63
B) 4.01
C) 9.3

Q4
E) 0.11
B) 0.6
C) 9.22

Q5
E) 0.0
B) 0.32
C) 8.09

Anybody have any ideas?  I'll see if I cant post some pictures as well.

[Andre]

The voltage at pin3 of IC2 should not be 0V.
If the LFO worked, you would measure a voltage which varies with the speed of the LFO.
Even if the LFO doesn't  work you should measure a voltage of about 1/2 Vcc here.
It seems to me there is a short between pin 3 and pin 4 (gnd) of IC 2.

The distortion you hear when probing C10 is probably caused by a misbiased BBD (MN3007).
VR3 is used to set the right bias with minimal distortion.

André

[krankguitarist]

Good call...I just looked a little closer and there's definitely a solder bridge there between R30 and R37.  Almost looked like there was a trace there, but after double-checking the layout, no dice .  I'll clean that up and see what happens.

[krankguitarist]

Eureka!  It works!  Finally I can go to bed!

Cheers Andre.  Thanks for the help!

[Andre]

You're welcome.

Is the distortion issue also solved ?

André