Cepheid Chorus - LEDs works and no chorus

[alvaro]

Hi to all,
First thaks, i've tried to made this beatiful pedal, but the chorus not works and the lfo (led) runs even when is down by spdt.
i upload the images to try to solve,
Wo any help, is apreciated because my knowledge of electronics is very basic, any orientation?

thanks a lot

 

[alvaro]

this is the values

 

[Ale_jellybelly]

I am not an expert myself having only built less than a dozen pedals but I can see several dodgy solder joints in your board. I'd try reflowing the board, maybe look up a couple of soldering tutorials.
make sure there are no shorts and look up the several trouble shooting posts about this pedal. Did you jumper the right spots according to the chips you have?

 

[chris.knudson]

I agree. there are definitely some suspect solder joints -- I would start by cleaning the board with some isopropyl and a soft toothbrush. However, I think your problem is that you have the 3207 and the 3102 in the wrong spots. I believe they are supposed to be swapped from what your picture shows.

EDIT: After looking at it again, you might have it right but the build docs may be wrong. What's on the BOM and the drawing on page 2 don't seem to match.

 

[BrainDrain]

I think I see 4 backward transistors.

 

[Locrian99]

That’s how the rate led works it’s always on whether the pedal is bypassed or not.

Are you passing signal but not getting a chorus effect?

Reflowing joints isn’t a bad idea. But this pedal has a small window on the trimmer where you get chorus effect. Try slowly turning the trimmer while you smack the low e or use a looper
Or have someone else play the guitar. It’s a pretty small window that you get the chorus effect. Once you’re in that window then you just fine tune for least distortion.

 

[Locrian99]

I think I see 4 backward transistors.

Now that you mention it I think they are all backwards. Hard to see the ones on the right very well.

 

[BrainDrain]

Yeah all those transistors need to be flipped 180 degrees. Everything else looks ok from the pics. Pretty sure Robert always arranges them so they're all the same direction.

 

[BrainDrain]

I agree. there are definitely some suspect solder joints -- I would start by cleaning the board with some isopropyl and a soft toothbrush. However, I think your problem is that you have the 3207 and the 3102 in the wrong spots. I believe they are supposed to be swapped from what your picture shows.

EDIT: After looking at it again, you might have it right but the build docs may be wrong. What's on the BOM and the drawing on page 2 don't seem to match.

The ICs in his pedal are correct and the build doc looks ok too.

 

[alvaro]

hi @Ale_jellybelly , yes i'll made with care reflowing and clean with isopropyl

 

[Locrian99]

You may have angered the pedal gods by not socketing your bbds, the pedal may be cursed now.

 

[chris.knudson]

The ICs in his pedal are correct and the build doc looks ok too.

You're right. I was looking at it upside down.

 

[alvaro]

hi @Locrian99, and tks i upload a new photo expecting was in correct way the transistors. expect the gods not angrered yet

 

[BrainDrain]

You're right. I was looking at it upside down.

I did the same thing at first too when I checked

 

[BrainDrain]

hi @Locrian99, and tks i upload a new photo expecting was in correct way the transistors. expect the gods not angrered yet

Unfortunately All of the transistors need to be flipped the other direction. The flat side of the transistor should match the flat side on the footprint on the PCB. I'd probably just clip them all off and start over if it were mine but maybe someone else has a better fix? I'd just clip the transistors so there's enough of the legs to be reused and also enough of the leg in the hole so you can pull it out when heated up and clear the holes.

 

[alvaro]

hi @BrainDrain, i take time to decide best position, but take the bad, jajjaja
it was only two ways and take the bad way. tks i'll revert it and tell us

 

[BrainDrain]

hi @BrainDrain, i take time to decide best position, but take the bad, jajjaja
it was only two ways and take the bad way. tks i'll revert it and tell us

No worries. It happens to all of us along the way. I've done my share of desoldering .

 

[alvaro]

hi @BrainDrain was this sounds it, i cant belive jjajajajajja

tks to anyone