Tyrian distortion issues

[MikeH.]

Hi, this is my first build, but I've done small electronics repair, amp repairs, and plenty of guitar mods in the past.
Currently working on the Tyrian distortion, have it all wired up currently but I'm not getting any distortion. Everything's lighting up, the LEDs are on all the time when the pedal is switched to the red or blue aggression mode, but the signal is weak and there is a little bit of a squealing sound. And when I toggle to the red or blue the squeal gets really loud. The only other problem I'm concerned about is the pad lifting on the 3rd leg of the gain pot on the board. Any thoughts or suggestions?

 

[Nostradoomus]

How bad is the lifted pad? You may need to run a jumper across lugs 2-3 of the gain pot as they need to be connected in this case.

 

[MikeH.]

The pad is lifted pretty bad on the top and bottom side of the board. Would that explain the squealing? I was concerned about the pad since it's the only visible issue. Figured I may have to jump it

 

[MikeH.]

 

[MikeH.]

The gain knob is on the left in the middle of the board. It's the square pad that's lifted on both sides.

 

[Nostradoomus]

Oh okay that’s lug 1, don’t jumper 2-3. Not sure on the V1 layout where R17 (56k) is but jump it there, follow the traces on the board.

 

[falzhobel]

I've had trouble with two of those PCBs in the last month, don't know if I scratched them or if they come defective but the two had broken link from the TL074 to the Ground. That causes weird issues (low volume, weird distorted tone). Had to track and compare with a working one to find the trouble.

 

[MikeH.]

Ouch... I hope I won't have to hunt too hard to fix this one lol

 

[falzhobel]

Have a look at voltage at each TL074 pins, if they are waving, that could be a problem.

 

[Robert]

I've had trouble with two of those PCBs in the last month, don't know if I scratched them or if they come defective but the two had broken link from the TL074 to the Ground.

That's unusual, it would take more than a scratch to isolate them from ground. Both TL074's are connected to the ground plane, they should have multiple paths back to ground. The upper one is connected via the top and bottom layers of the board.

 

[falzhobel]

That's unusual, it would take more than a scratch to isolate them from ground. Both TL074's are connected to the ground plane, they should have multiple paths back to ground. The upper one is connected via the top and bottom layers of the board.

I shorten my explanation but it was between the TL074 and a Capacitor going to the ground that the link was weak, I had to put a wire and everything was good.

I was getting weird floating voltage before doing that.