Musikding Screamer v2

[darko1002001]

Hello all,

I am trying to build one of my first pedals and i have bought and following the DIY kit for Screamer V2 from musikding.de

Here is the link:
https://www.musikding.de/The-Screamer-Overdrive-kit

The schematic is here:
http://diy.musikding.de/wp-content/uploads/2013/06/screamerV2_schalt.pdf

I have issues getting it to work.
The current state of things is as follows:
- When the switch is off, the signal goes through, everything works ok.
- When the switch is on, led is lit up, and i can hear a very quiet sound of if i turn all the knobs to max.

What i tried so far.
Well since its my first build i don't really have an idea on how to completely debug this (thus reaching out to you all    ), but:
- I have looked over the parts and components and the layout and i cannot seem to find any errors.
- I also compared it with some images i found on google of the exact build, still couldn't see a difference.
- I also tried to clean up any components that might be soldered together by either using the iron or a scalpel.

I used only the parts that came with the kit, no replacements.

Here are photos:

https://drive.google.com/file/d/1Q5criV2C-pDLC3v8E-sPXG3DF5v2msFLRA/view?usp=sharing
https://drive.google.com/file/d/1WlF2RkrMWzXo9rZLrFDWOvfQ5dkVu6ANYA/view?usp=sharing
https://drive.google.com/file/d/1h5KAzW3Glhjq5zyNvUyZaKEwCyE_o_TjvQ/view?usp=sharing
https://drive.google.com/file/d/1lCfbT4JMr0u13zTYtKBRVa9ccIWZnMBURg/view?usp=sharing
https://drive.google.com/file/d/16QSK_BJeevpL54YcKBk78hXltclBoP20-g/view?usp=sharing
https://drive.google.com/file/d/1JWjyGGw4B6B-_vJ2dgDSNIAPcY67qGSfqw/view?usp=sharing

I am posting photos of my build and the values i can read with the multimeter.

Here is what i measured, seems

Power level from adapter: 9.33 V

IC

1: 4.58
2: 4.96
3: 4.54
4: 0
5 4.58
6: 4.59
7 4.59
8: 9.31

T1:
E: 3.17
B: 2.79
C. 9.31

t2:
e 3.14
b: 2.67
c 9.31

C8: 4.06
C9: 3.05
C 10: +3.17  | -0 -
C11: + 9.30 | -0

C12 + 4.60 | 0

D4:
A 0
K  9.30

R12: 4.30
R.16: 0 on both sides

Update 1:
Now i am getting power at t2 also C10, t2 has pretty much the same values as t1 which i think its ok. updated the values above.
Still nothing at r16 on both sides.

[Kipper4]

Welcome aboard the good ship Debug and the forum.

Something funky is going on with T2

T1 is essentially the same as T2 so one would expect the same voltages.
Suggesting perhaps a bad connection at R13....

[darko1002001]

OK so i fixed that one it seems, i updated the values of t2 now. getting 3.14  2.67 and 9.3.

But still doesn't work, now i don't get even the quiet sound.

[nonoxxx]

Values seems not bad you should audio probe the circuit

[nonoxxx]

Unsolder the out from the dpt board, solder a 1uf cap on the lead and solder another wire on the cap and you can debug your circuit by placing the wire on each signal compnents  ´ http://www.coda-effects.com/2015/07/troubleshooting-guide-for-guitar.html

[darko1002001]

OK i made a working probe,
Something is not clear to me. Here is what i do with it:

Touch the input - There is sound
Touch the green wire on the board (says out) and there is sound but its actually the input sound (which is strange to me)
Touch the blue wire and no sound comes through

I should go from in towards out in the circuit right? i should invert the wires (green and blue one)?

[darko1002001]

OK so inverting the in and out wires actually solved the issue, everything seems to be working now.

[Kipper4]

http://www.geofex.com/Article_Folders/TStech/tsxtech.htm

If you look at the diagrams in the above article. Each diagram show an IN from and To (output)
This is where you probe to follow the AC (music signal) through the circuit.

Probing just the guitar input and effect output tells you no more than you already know from plugging the guitar into the effect and its output to your amp.


"Now i am getting power at t2 also C10, t2 has pretty much the same values as t1 which i think its ok. updated the values above.
Still nothing at r16 on both sides."

You wouldnt expect to see any DC voltages at R16 because the 10uf output capacitor blocks DC (but not AC) from getting to the output and R16. So thats as expected.

Not bieng funny here but double check you are not plugging the guitar into the output and vice versa.
I say this because i've been there.

I havent looked at the pictures yet.
You'll get there just be patient and work through methodically.
Rich

[darko1002001]

Thanks!

Not bieng funny here but double check you are not plugging the guitar into the output and vice versa.

You are actually right about this, i actually inverted the in/out wires when i should have just switched the in out cables. Its a lesson

Everything works now.

Thanks for all your help.

[Kipper4]

Excellant.
I've made some dumb gaffs. It's how I learn.
Glad it's working.
Rich

[duck_arse]

just for fun, can you remeasure the transistor voltages please? the base voltage needs to be higher than the emitter for the transistor to work, is my understanding. and welcome.

[darko1002001]

just for fun, can you remeasure the transistor voltages please? the base voltage needs to be higher than the emitter for the transistor to work, is my understanding. and welcome.

I have updated the readings in my initial post in this thread. i get the same readings for t1 and t2 it seems. and B < E

[PRR]

> base voltage needs to be higher than the emitter

This one has huge base resistors. I will assume (since it works) that the low reading on B is just meter loading.