Swamp Thang Problem

[cns0270]

Hi all,

New to the site and have built 3 successful pedals this far. But, I just completed building the Swamp Thang tremolo and am experiencing the following issue.

The only time I get signal is if the intensity know is turned fully clockwise. Once I back off of it, the sounds cuts out. And, even when the knob is maxed, I do not get the trem. Could this be. Bad pot? I checked and rechecked for bridges under a microscope and do not have any. The only thing peculiar about this build is that two of the caps are axial caps but, I do know that the negative lead is the one coming from the aluminum side so, I don't think (know) that it could be the issue.

Any helper guidance would be greatly appreciated. And, I absolutely love this site. I have always wanted to make my own pedals and now I can (kind of, apparently). Much thanks to all of the effort that goes into this site.

Best,
Chris

[IvIark]

Measure all transistor pin voltages and post them.  They always give the best clue

[cns0270]

Thank you, Mark. I don't currently own a DMM but, am looking to get one soon. Possibly tomorrow. But in the meantime, I always order one extra of each component when I do a build. So, is there anything you would suggest replacing to see if that helps? I did not order extra pots but will be ordering one tonight just in case. I did replace the transistors to no avail.

Thanks again.

[cns0270]

Think I have it figured out. Put a 270ohm resistor in place of the 270k resistor. This resistor is directly tied to the intensity knob. So, off to the store to pick up a 270k and a DMM.

[cns0270]

So, replaced the 270r with the 270k and still nothing. I also picked up a DMM and took transistor readings.

Q1: C- 9.71
       B- 1.25
       E- .65

Q2: C- fluctuates between 2.78- 4.52
      B- .66
      E- .oo

Q3: C- 0.00
       B- .70
       E- 0.00

Q4: C- 2.11
       B- 1.69
       E- 1.15

Again, any help is appreciated.

[cns0270]

Disregard. Fixed and working. Thanks again.

[rocket88]

What ended up being the problem? Would be great to know in case one of us ends up running into a similar issue. Btw, glad to know you got it working.

[cns0270]

I ended up putting the back under my magnifying glass and running through the tracks to make sure they were free and clear with no bridges. Then, I painstakingly reflowed all of my solder joints. It fired up after that.