Tube Screamer flatulence, needs help. Q voltages included...

[markr04]

Hi all.

The Tube Screamer (http://www.tonepad.com/getFile.asp?id=81) I built farts on very hard strums and is silent otherwise. I swapped the almighty mojo chip thinking that was bad, but didn't solve the problem. It was suggested that the bias(es) for the 3904s was off and I should test and post the voltages:

Q1
E: 2.98
B: 3.47
C: 8.77

Q2
E: 3.14
B: 3.61
C: 8.77

[petemoore]

Well they look consistant. What does the audio probe say about their function?
 I'm not used to reading bias voltages of transistors used for buffers.
   Probe them and the OA, also post the Opamp pin voltages.

[Fret Wire]

Here's the transistor voltages from GGG's TS build, same transistors. Scroll to to the bottom of the page. Yours look good, sounds like the problem might be elsewhere.

http://www.generalguitargadgets.com/instructions/tscmr_inst.htm

[brett]

Just a guess, but it could be an IC bias problem.  Check the voltage at the input to the first stage, the tone section, and the second stage.  They should be  about 1/2 the supply voltage.  That's pins 1,2,3,5,6,7.  

good luck

[Phorhas]

More than one I has this problems with TSs, both DIY and Ibanez made...

An educated guess is that you have short some where... my TS (my first pedal ever bought) had that problem and it sat in a closet for about a year. OI didn't know what was it's problem but deccided to mod it, since it should be operated anyhow. after an 808 mod it still had the problem - than I noticed that one of the pots turned abit and one of the lugs touched the chasis...

[R.G.]

It was suggested that the bias(es) for the 3904s was off and I should test and post the voltages:

That was me, and actually I didn't suggest that the biases for the 3904s was off, I suggested that a bias somewhere was off and that you measure and post the voltages on all pins of all transistors and ICs. Can you do that?