Cepheid Chorus no chorus effect

[cjones132002]

Hey all,
I've seen some stuff on troubleshooting this PCB but no answer found. I built the pedal, LEDs function, it works in bypass and when I engage the effect it's just my guitar signal with no chorus effect. I've built probably 10 pedals at this point and never had an issue. I'm not sure what step I should take, the kit was from stomp box parts website so everything was provided. It's just odd that the pedal completely works in passive or engaged it just has no effect.
Let me know what you think, anything appreciated!
Cheers,
Chris

 

[eh là bas ma]

The first thing that comes to mind is calibration. If the BBD trimmer isn't set correctly it won't do any modulation.

Try to turn it slowly when the circuit is activated, with a guitar signal going in the circuit. The modulation may appear at some narrow spot in the trimmer's rotation.

If i understood correctly, BBD chips can be counterfeit depending on your supplier. For example, buying BBD chips on e-bay isn't a good idea.

I can see some suspicious soldering joints on your build, and some possible shorts, you might want to reflow them and clean the tiny spaces between pads :


Don't forget to remove all heat-sensitive parts (ICs, transistors) before using your iron in the aera.

If you need a more in-depth troubleshooting work, you might want to check this article to see how to write your post :

DEBUGGING - What to do when it doesn't work

DEBUGGING - What to do when it doesn't work

www.diystompboxes.com

 

[Nic]

Since it's a kit, and signal is passing, my bet would also be the trimmer. Have your pots turned on, and turn the trimmer while strumming a note, slowly, really slowly. The range where you will get the effect is small. Still, a bad BBD could be at cause

 

[cjones132002]

The first thing that comes to mind is calibration. If the BBD trimmer isn't set correctly it won't do any modulation.

Try to turn it slowly when the circuit is activated, with a guitar signal going in the circuit. The modulation may appear at some narrow spot in the trimmer's rotation.

If i understood correctly, BBD chips can be counterfeit depending on your supplier. For example, buying BBD chips on e-bay isn't a good idea.

I can see some suspicious soldering joints on your build, and some possible shorts, you might want to reflow them and clean the tiny spaces between pads :
View attachment 67054

Don't forget to remove all heat-sensitive parts (ICs, transistors) before using your iron in the aera.

I'll try to adjust the trim pot. I ordered all my parts from stompboxparts.com so I'm not sure where they source the parts but I built one of the chorus pedals from them before with no issue. I went through and tried to reflow some of the solders but I've not had any soldering issues in the past since I do a lot of soldering for work. I just felt it was so weird that the pedal completely works even when the effect is engaged, it just had no effect haha.

 

[cjones132002]

Since it's a kit, and signal is passing, my bet would also be the trimmer. Have your pots turned on, and turn the trimmer while strumming a note, slowly, really slowly. The range where you will get the effect is small. Still, a bad BBD could be at cause

Thanks so much! I'll try that now and let ya know if I find anything

 

[DGWVI]

Each of these two sets of pads needs to be jumpered/ soldered together



For better illustration, here's a shot from @MichaelW's build report-

 

[cjones132002]

Each of these two sets of pads needs to be jumpered/ soldered together

View attachment 67055

For better illustration, here's a shot from @MichaelW's build report-
View attachment 67057

Good to know. I don't think I did that on my last chorus build but the PCB was also slightly different on my last build too. I'll try that too

 

[DGWVI]

Good to know. I don't think I did that on my last chorus build but the PCB was also slightly different on my last build too. I'll try that too

With those pads open, your BBD isn't getting any power

 

[Nic]

Good to know. I don't think I did that on my last chorus build but the PCB was also slightly different on my last build too. I'll try that too

That board will accept different bdd, but need to be jumpered accordingly.

 

[cjones132002]

Each of these two sets of pads needs to be jumpered/ soldered together

View attachment 67055

For better illustration, here's a shot from @MichaelW's build report-
View attachment 67057

You're right! Thanks so much! This worked, don't know how I missed this!
So appreciate you!