SOLVED Woodpecker Tremolo not modulating

[chris.knudson]

I was hoping to post a successful build report tonight, but my Woodpecker Tremolo isn't modulating. I get a good bypass signal, and the pedal powers on and passes signal, but I'm not getting any effect out of it. The Depth and Rate controls don't seem to do anything. The Level works, but I can barely get to unity gain with the level all the way up. I'm guessing that it has to be the transistors, right? I'll try swapping them out tomorrow, but was wondering if anybody else had any ideas.

 

[Erik S]

Pretty sure I had the same problem with mine caused by some bad/ fake 2n6027s I got on eBay. I took the advice of somebody here and ordered some central branded ones from mouser and that cleared it up.

 

[chris.knudson]

Pretty sure I had the same problem with mine caused by some bad/ fake 2n6027s I got on eBay. I took the advice of somebody here and ordered some central branded ones from mouser and that cleared it up.

Yeah, I suspect it's either the 2N6027 or the 2N5089. I'm not sure where I got these -- probably from Amazon.

 

[Erik S]

I think the 2n6027 is the one that handles the modulation, and it's the one that's harder to find. I'd definitely start there.

 

[Robert]

I'm putting in an order with Mouser today, want me to grab you one of each to save on shipping?

 

[chris.knudson]

I'm putting in an order with Mouser today, want me to grab you one of each to save on shipping?

That would be be awesome. Thanks.

 

[jimilee]

Instead of a PF5102, I used a J201, works fantastic as far as levels go. If I’m remembering correctly, the. Plume does have to be turned up quite a bit, definitely not dimed though. I had to get my 6027 from mouse as well. I got some takes off of eBay. The dude swore the were originals. I told him someone lied to him.

 

[chris.knudson]

Instead of a PF5102, I used a J201, works fantastic as far as levels go. If I’m remembering correctly, the. Plume does have to be turned up quite a bit, definitely not dimed though. I had to get my 6027 from mouse as well. I got some takes off of eBay. The dude swore the were originals. I told him someone lied to him.

Cool, I'll try the J201. I mean I can get it to unity, but I don't feel like I should have to dime it to get there.

 

[Robert]

EDIT:
Remove the 5089 and see if the volume comes up.

 

[chris.knudson]

I think the 2n6027 is the one that handles the modulation, and it's the one that's harder to find. I'd definitely start there.

Tried another 2N6027 that I had (from the same batch) - still not modulating

Instead of a PF5102, I used a J201

Tried this - no change

Remove the 5089 and see if the volume comes up.

Tried that - no change

I have six other pedals on the bench ready to be boxed -- think I'll shift gears until I can get a new 2N6027 - I'm pretty sure the ones i have are fake or bad.

 

[Robert]

I haven't built one of these in a while so I can't remember what the output level was like, but, a good 5089 / 6027 isn't going to give you more volume than you have right now.

Removing the 5089 takes both of those completely out of the circuit. The modulation cuts volume, not increases.

Assuming the output level isn't normal, this is where you'll want to focus, you can ignore everything else until that's corrected.

 

[chris.knudson]

I haven't built one of these in a while so I can't remember what the output level was like, but, a good 5089 / 6027 isn't going to give you more volume than you have right now.

Removing the 5089 takes both of those completely out of the circuit. The modulation cuts volume, not increases.

Hmmm, then I have another problem. I'm sure there should definitely be more volume than I am getting. I'll double check the values on all the resistors and go from there.

 

[jimilee]

I’m guessing g you’ve already reflowed your solder as well.

 

[Robert]

Are you sure your J201 is genuine?

 

[chris.knudson]

Well, I found a couple of resistor values that I got wrong:
Looks like I put a 1k in R1 -- supposed to be a 1M
Looks like a 4.7K in R11 -- supposed to be a 47K
And looks like a 2.2K in R7 -- supposed to be a 220K

Must have been one of those late nights after a drink or two...

Are you sure your J201 is genuine?

I'm guessing that they are - I've used them on other projects without a problem, but who knows. I have a bunch of them that I got from different suppliers -- could have some bad mixed in with the good.

 

[chris.knudson]

I’m guessing g you’ve already reflowed your solder as well.

I always reflow and inspect every joint after I finish a board.

 

[jimilee]

I always reflow and inspect every joint after I finish a board.

You are the man. We got into a huge long post where that ended up being the issue like 5 pages in.

 

[chris.knudson]

I still suspect that my 2N6027 is a fake, but I'll swap out those resistors and see where that gets me.

 

[chris.knudson]

You are the man. We got into a huge long post where that ended up being the issue like 5 pages in.

My soldering isn't always the prettiest, but I like to make sure that I've got got a good solder joint that flows through the board and connects to the pads on both sides of the board and that I don't have any solder bridges anywhere.

 

[chris.knudson]

I haven't built one of these in a while so I can't remember what the output level was like, but, a good 5089 / 6027 isn't going to give you more volume than you have right now.

Removing the 5089 takes both of those completely out of the circuit. The modulation cuts volume, not increases.

Assuming the output level isn't normal, this is where you'll want to focus, you can ignore everything else until that's corrected.

View attachment 65102

I'm guessing R1 is my problem -- looks like I'm sending too much of my signal to ground right from the get go.