Trouble with Danelectro Cool Cat chorus

[Delay]

I bought this pedal used and i've got a big trouble: the sound goes right through the pedal in bypass but when the pedal is on (the led lits up) the sound is the same as when the effect is off, no chorus effect at all, just the bypassed sound.

Looking at the pcb it seems everything's ok, no burned components, every diode and every ICs are working. I've also try to resolder the bypass switch and the pots to avoid some possibile cold solderjoint, but nothing has changed...so, i'm asking you..what's the possible error? 

Another big problem is that there's no schematics of this pedal on the web..!

Thanks in advance!
Filippo

[R.G.]

Since a chorus is one of those pedals that mix the dry sound with the processed sound to make the final effect, it seems that no sound is getting through the delay.

So it might be anything in the delay path.

[343 Salty Beans]

Seems like a tough fix  good luck. You'll probably have to trace the signal...look for the delay/timer chips on the board, and the components around them. Using an audio probe will REALLY REALLY REALLY REALLY help...I cannot stress this enough. Follow the signal from the input. If the signal doesn't even get through to the delay chip, your problem will be a short/bad component in all likelihood. If you get to the delay chip but there's no sound at the output, it's either a short or a bad chip :/. If the pedal's more than ten years old, it's possible that the electrolytic caps went bad...

but I'd say use the audio probe first. It is probably the most handy tool I've ever had, and I only realized that after debugging my paralooper last night and today. Good luck again, hope you get it working.

[Delay]

Ok, i just build and audio probe and start testing the circuit..!
A very bad deal is that i don't have a schematic, but i'll try anyway!   

I've notice two thing (first of all: I'm really a beginner in electronic theory):

1) At the input (pin 3) of the CD3207 (i think is the delay chip..right?) there's signal, but at the output (pin 7-8) there's NO SIGNAL...CD3207 is broken?

2) At the clock output (pin 2 - 4) of the CD3102 (i think is the clock generator..right) there's no signal, but maybe the audio signal doesn't go througt it...right?

I've to change both of them? Or everything is ok, and the problem is another place?

Thanks!

[Mark Hammer]

A common issue with BBDs is the need to provide a dependable bias voltage for the audio signal to "ride" on.  I do not know the specifics of the Cool Cat, but there are two common strategies used in chorus pedals to provide that bias voltage.  One is a trimpot feeding the input of the BBD directly (through a fixed resistor), and the other is to use the Vref (i.e., virtual ground used for the rest of the audio path) as the bias voltage.  I don't know which of these two the Cool Cat employs, but it is easy enough to determine if there is a single fixed resistor between the input pin (pin 3) and a nearby trimpot.

Trimpots are normally pretty sturdy, and are often secured in place after factory adjustment by a dab of something that dries and hardens.  On the other hand, they ARE pots and subject to all the same discontinuity issues of pots.  As well, pedals spend their lives getting kicked around.  So, while you can easily compensate for how youir volume pot got jiggled on stage, re-adjustment of a jarred-loose trimpot on the inside is another matter.

These can be adjusted by ear with decent results.  Note that the delay sound will be audibel when it is set bang on, and will be audible but distorted when the bias voltage is set a little high or a little low.  When the bias is too far off, there will be no sound audible from the BBD, and no signal coming out despite signal going in.

That is not to say that the BBDchip is NOT fried.  Rather, it is one way of an otherwise decent chip seeming fried when it isn't and costs nothing to check out.  Do not be worried about doing damage by adjusting the trimpot (should there be one) too high or too low.  The only thing you will lose will be audio signal...until you adjust it right.

[Delay]

IT WORKS AGAIN! 
The CD3207 was damaged, i replace it with a new one and now the chorus works! It's also a very great sounding pedal..!
Thanks a lot to everyone!
Filippo.