help with "corral chorus" ce2

[natalio]

Hi, I have just passed all day trying to make it work, but I still cant.
The problem i have i that the output is exactly identical to the input, no chorus is present.
I am building this based on the pdf available at tonepad (thanks FP), all the parts are just like listed, the only change is a tl 072 instead of the tl 022 ,
http://www.tonepad.com/project.asp?id=53
I have tested all vcc and gns points on the circuit and ICs, and they are all just as espected.
Any sugestions about what is hapening here?

[Andre]

Hi Natalio,
In order to help you we need more information.
Please read the "what to to when it doesn't work" thread and then  report back.

André

[natalio]

Im so sory about that, it was a 2 am "im so tired of this" post.

I am using no mods, ust the default schematic.

The voltage readings at the ICs are:

IC1:

4,53
4,53
4,46
0
4,5
4,53
4,5
8,95

IC2:

8,91
4,5
6,93
0
4,46
2,33
4,5
8,96

MN3101:

8,86
4,54
0
4,59
0,31
7,81
3,03
0,59

MN3007:

8,86
4,59
0,32
0,52
0
4,54
3,52
3,52


I have checked the entire circuit five times, still cant find an error.
Also tried to change all the ics, and still effect.


The output of the circuit is exactly the same as the guitar signal.

Thanks for your help!

[Andre]

Here are the voltages as measured on my Tonepad CE-2



One of the differences I see between your voltages and mine is  the voltage at pin3 of the MN3007.
This pin should measure about 4.5 to 5.5 volts. This voltage is important because it is the bias voltage for the BBD.
If there's no bias voltage or wrong bias voltage, there will be no signal coming from the BBD.
Please check if Q2 is the right type and has the right orientation.
If both are OK please measure the voltage at the base of Q2. Here the voltage should be between 5 and 6 Volts.
If this voltage is OK, the transistor is bad.
If not,the voltage at the base of Q2 is supplied through resistors R11,10,9,and 8 and comes from Vb.
My guess is vb is OK, as there is an output signal, so maybe there's some bad soldering on one of the pins of the resistors R8 to R11.

André

[natalio]

Andre, thanks so much for your help, I realized that it was just a minimal scratch in the copper surface that caused an "open circuit" in the bias plane.
Now it is allready working, and it sounds really awesome.
Thanks!