musikding Screamer with (almost) no sound (SOLVED)

[Sardus]

Hello to everyone,
this is my first post, hope to have some help here. Please forgive my poor english 
I'm in trouble with my second project, the first one (musikding factory fuzz) works pretty well.
The pedal is the screamer from musikding.

Here the schematic:
http://diy.musikding.de/wp-content/uploads/2013/06/screamerschalt.pdf
Here the wiring layout:
http://diy.musikding.de/wp-content/uploads/2013/06/screamerwire.pdf

I'm not a newbie with soldering, so while I was assembling the kit I found an error on the PCB

As you can see in the red circle I found a contact between the resistors R8 and R10, I wrote shortcut, but of course I meant short circuit  ..ooops:icon_rolleyes:

Here you can see a good PCB:


In this pic finally I explain how I fix the problem:


I quickly report this problem to Musikding of course, but they are on Holidays (however I see today that they removed the kit from store), so I'm still waiting for a response.

This is the situation:

The true by pass works fine
When I switch on the pedal the led turn on
(I changed the original red one with a blue one)
I hear a pop (not really good)
The volume is really really low

I use a 9vdc power supply, here the measurements in Volts:

Q1
C = 9.1
B = 3.62
E = 3.16

Q2
C= 9.1
B= 3.59
E= 3.14

IC1
P1= 4.59 p5= 1.7
P2= 4.61 p6= 8.2
P3= 4.59 p7= 8.37
p4= 0      p8= 9.1

D4
A = 2
K = 9.1

D1 (zener)
A = 4.6
K = 4.59

D2 (zener)
A = 4.38
K = 4.61

D3 (zener)
A = 4.6
K = 4.38

Please give me a any advice, I'm stuck here..
Thanks a lot


edit:
here a shot of my unscreaming screamer

[roseblood11]

Did you post this to the musikding forum?

[Sardus]

no, I just gave a report to the support. The musikding forum is in german, but I'll give a try. I'm going to.

[samhay]

You have a problem around the second op-amp / tone control, where it looks like the non-inverting input (pin 5) is being pulled to ground. As this is where you 'fixed' the PCB, I would start by double-checking whether there was actually anything wrong with the layout to begin with.

[Sardus]

woww!!
I'm impressed, you find a another problem on the PCB that I miss!!!
I follow the circuit from pin 5 as you said and I find this:




I'm going to fix it, hope that I am doing right 

[Sardus]

You have a problem around the second op-amp / tone control, where it looks like the non-inverting input (pin 5) is being pulled to ground. As this is where you 'fixed' the PCB, I would start by double-checking whether there was actually anything wrong with the layout to begin with.

So there was the problem!!
Now the Screamer play fine (I tried it for 1 minute, Im going to give it a better try )
Thanks a lot samhay, your are my hero!!!
just one thing please!!!!
I still heard a big pop when I press the switch, is there a fix? I made some other mistakes??
thanks again

[peterg]

Welcome to the forum! Resistor R1 should take care of the switch popping. Did you install a 2M2 resistor as per the schematic?

[Sardus]

Welcome to the forum! Resistor R1 should take care of the switch popping. Did you install a 2M2 resistor as per the schematic?

Hello pterg, Yes I did but Im going to measure it.

[Sardus]

R1 is 2,2M 
any other suggestions?


edit:
ok ok, just find another PCB mistake..
LOL

[Sardus]

And here we are!!!!!


Now it's perfect!!!!!!!!!!
thank you all!!!!

[samhay]

Glad you got it fixed, and sounds like you should pass on your experience to the das Musikding forum.