TS-808 Debug

[markmcconachie]

Hey, got started with stomp box building last week when I build a Dr Boogie, it worked really well after biasing.

I then decided to build a TS-808 from a kit I bought at Musikding.de
http://www.musikding.de/product_info.php/info/p1618_The-Screamer---Overdrive-kit.html

Project info
1.Name of the project: Tubescreamer TS-808 (Der Screamer)
2. All docs are found here http://www.musikding.de/product_info.php/info/p1618_The-Screamer---Overdrive-kit.html
3. I followed the layout 100% using the two resisters to make an 808 rather than a ts9
4. All the parts came with the kit so I didn't substitute anything
6.

Okay, the issues that it is having...

Bypass works. When not bypassed LED comes on but no sound.

I have checked all the soldering, seems pretty okay to me.
I have checked that each component matches the schematic, this included me using a DMM to measure resistors. Everything is correct.
I checked polarity of caps and diodes... all as should be.
Next I decided to make audio probe, traced audio until pin three of the IC and no further.

Used DMM to check voltages up to the IC. All read 8.9V except pin 4 (ground).
I expected only pin 1 to read 8.9V.

I rechecked the resistors and caps up to that point.

I then decided to measure the values to the IC socket when there was no IC installed.

They read as I had originally expected. 8.9V on 8, 4.2V on everything except 4 with 0.

I have tried pretty hard to get this to work and don't really know what the next step is...
I am starting to think that the IC is faulty?

Can anyone help me? Thanks!

EDIT

Recorded Voltages on Q1 and Q2

Voltages on Q1

WITHOUT IC1 installed
2.73   2.45   8.76

WITH IC1 installed
1.9    1.85    8.78

Voltages on Q2

WITHOUT IC1 installed
2.75    2.47   8.77

WITH IC1 installed
1.91    1.85    0

[J0K3RX]

Check your wiring... Go here http://www.tonepad.com/getFileInfo.asp?id=76

click on download file then look at wiring diagram number 5

[markmcconachie]

I have checked it many times already following this diagram
http://diy.musikding.de/images/stories/screamer/screamerwire.pdf

Which I believe is functionally the same except for the handling of the LED...

I verified that wiring was okay using the audio probe

[Pettol]

I don't have a solution for you unfortunately, but I have built two TS808 from musikding and they worked great (so there is nothing wrong with the pcb or the documentation). I can only advice you check everything again.
Use the audioprobe and follow the signal through the entire circuit.That usually reveals where there the problem is.
Also, check that all strands of the wires are soldered together. It's easy to miss one, with shorts as a result...

[petemoore]

  Used DMM to check voltages up to the IC. All read 8.9V except pin 4 (ground).
I expected only pin 1 to read 8.9V.
   What is the voltage you read where it should be 1/2v at the Voltage divider [two equal value resistors strung across the power supply rails]...then the 'bias feed' resistors connecting the Vdivider and the opamp input pins.
  The voltage divider provides a 1/2v reference which, through the bias resistors for the opamp pins [look for where R's occur betweeen the V divider and opamp input pins, on the schematic]...check the values of these resistors, and that something near 1/2v occurs at the V divider.
   All the pins seem to have a common problem, the V divider is close enough to all of them to throw all of them off-bias.

[markmcconachie]

Voltage between the voltage dividers is 4.2V, so it seems to be okay... I should have added that sorry.

[markmcconachie]

I don't have a solution for you unfortunately, but I have built two TS808 from musikding and they worked great (so there is nothing wrong with the pcb or the documentation). I can only advice you check everything again.
Use the audioprobe and follow the signal through the entire circuit.That usually reveals where there the problem is.
Also, check that all strands of the wires are soldered together. It's easy to miss one, with shorts as a result...

I followed the signal and it stops at IC1.

[Govmnt_Lacky]

So....

When the IC is installed, you get 8.9V on ALL pins EXCEPT FOR Pin 4 

When the IC is removed, you get 8.9V on Pin 8, 0V on Pin 4, and 4.2V on the rest. 

Other than having the IC in backwards, it seems like you found your answer 

[markmcconachie]

So....

When the IC is installed, you get 8.9V on ALL pins EXCEPT FOR Pin 4 

When the IC is removed, you get 8.9V on Pin 8, 0V on Pin 4, and 4.2V on the rest. 

Other than having the IC in backwards, it seems like you found your answer 

The little circle should be next to pin 1, yea?

[Govmnt_Lacky]

The little circle should be next to pin 1, yea?

Yep! 

[markmcconachie]

The little circle should be next to pin 1, yea?

Yep! 

Okay, I ordered a couple of spares. Should get them by the end of the week.

Thanks for the help everyone

[markmcconachie]

Just an update incase anyone finds this thread when they are having similar issues.

I changed the chip today and it worked perfectly.

I was lucky to be using a socketed chip. I ordered a few chips to choose which I like best.

[Seven64]

i personally liked the 4558D in mine the best.  the ne5532 and opa2134 were a close 2nd.  nothing else appealed to me

[markmcconachie]

I have the 4558P now and I like it. I so far have tried an RC4559P which was nice but produced too much gain.

I ordered every opamp that I could find that has the same pin config