Hello to everyone,
this is my first post, hope to have some help here. Please forgive my poor english :icon_redface: :icon_redface: :icon_redface:
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 (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 (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
(http://oi61.tinypic.com/34spbif.jpg)
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:
(http://oi59.tinypic.com/90c1nk.jpg)
In this pic finally I explain how I fix the problem:
(http://oi59.tinypic.com/ohkeir.jpg)
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
(http://i59.tinypic.com/1zykbgo.jpg)
Did you post this to the musikding forum?
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.
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.
woww!!
I'm impressed, you find a another problem on the PCB that I miss!!! :icon_idea: :icon_idea:
I follow the circuit from pin 5 as you said and I find this:
(http://oi61.tinypic.com/11kcg2g.jpg)
I'm going to fix it, hope that I am doing right :-\
Quote from: samhay on August 16, 2015, 11:34:44 AM
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 8))
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 :D
Welcome to the forum! Resistor R1 should take care of the switch popping. Did you install a 2M2 resistor as per the schematic?
Quote from: peterg on August 16, 2015, 12:41:08 PM
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.
R1 is 2,2M :(
any other suggestions?
edit:
ok ok, just find another PCB mistake..
LOL
(http://oi58.tinypic.com/opo3za.jpg)
And here we are!!!!!
8) 8) 8) 8) 8) 8) 8) 8)
Now it's perfect!!!!!!!!!!
thank you all!!!!
:icon_biggrin: :icon_biggrin: :icon_biggrin:
Glad you got it fixed, and sounds like you should pass on your experience to the das Musikding forum.