Author Topic: musikding Screamer with (almost) no sound (SOLVED)  (Read 403 times)

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Sardus

musikding Screamer with (almost) no sound (SOLVED)
« on: August 16, 2015, 01:15:33 AM »
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
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
« Last Edit: August 16, 2015, 07:47:59 AM by Sardus »

roseblood11

Re: musikding Screamer with (almost) no sound
« Reply #1 on: August 16, 2015, 02:28:00 AM »
Did you post this to the musikding forum?

Sardus

Re: musikding Screamer with (almost) no sound
« Reply #2 on: August 16, 2015, 02:30:19 AM »
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

Re: musikding Screamer with (almost) no sound
« Reply #3 on: August 16, 2015, 05:34:44 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.

Sardus

Re: musikding Screamer with (almost) no sound
« Reply #4 on: August 16, 2015, 06:14:49 AM »
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:




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

Sardus

Re: musikding Screamer with (almost) no sound
« Reply #5 on: August 16, 2015, 06:29:38 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

peterg

Re: musikding Screamer with (almost) no sound
« Reply #6 on: August 16, 2015, 06:41:08 AM »
Welcome to the forum! Resistor R1 should take care of the switch popping. Did you install a 2M2 resistor as per the schematic?

Sardus

Re: musikding Screamer with (almost) no sound
« Reply #7 on: August 16, 2015, 07:08:35 AM »
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

Re: musikding Screamer with (almost) no sound
« Reply #8 on: August 16, 2015, 07:25:37 AM »
R1 is 2,2M  :(
any other suggestions?


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

« Last Edit: August 16, 2015, 07:36:10 AM by Sardus »

Sardus

Re: musikding Screamer with (almost) no sound
« Reply #9 on: August 16, 2015, 07:47:37 AM »
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:

samhay

Re: musikding Screamer with (almost) no sound (SOLVED)
« Reply #10 on: August 16, 2015, 09:09:58 PM »
Glad you got it fixed, and sounds like you should pass on your experience to the das Musikding forum.