# Caesar Chorus, no effect



## Sparky_mark (Jan 22, 2022)

Hi, I’m in need of help with the Caesar Chorus. I’m getting a clean signal when turned off but nothing when engaged.
I’ve done a signal trace and getting sound from R1 but I gets weaker from C1 and so on till nothing at R3 or 5.
It’s coming in fine from the input jack, just loses it fast. 
Thinking maybe to I'll have to replace a resistor or two at the beginning on the signal path but I'm not sure what.
I’m about at the end of my knowledge of what to do and need help!!
Thanks you!


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## JamieJ (Jan 22, 2022)

Have you tried to clean the board? It looks well covered in flux residue which is making your joints look dirty. That makes it hard to see which one may be cold. There are a few there that might be worth reflowing but I’d clean the board first with IPA. 

Also where did you get your 3207 and 3102? There are lots of fakes out there.


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## Sparky_mark (Jan 22, 2022)

JamieJ said:


> Have you tried to clean the board? It looks well covered in flux residue which is making your joints look dirty. That makes it hard to see which one may be cold. There are a few there that might be worth reflowing but I’d clean the board first with IPA.
> 
> Also where did you get your 3207 and 3102? There are lots of fakes out there.


I’ve since given it a good scrub with IPA and gone over the joints to see if any bridges. 
I got the V3102D from antique electronic supply, I’m assuming it’s a real one but you never tell. 
The other I got off another user on here who had used ones in his build.


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## Sparky_mark (Jan 22, 2022)

An update to anyone that might be able to help. I found one problem, I put a 470R instead of 470k for R5. Changed that and got signal through the pedal when turned up…but no effect and when the blend knob is turned to max all sound shuts off. 

So fixed one problem and found another!


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## Big Monk (Jan 22, 2022)

You said you get signal in bypass. 

Do the LEDs work too?


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## Stickman393 (Jan 23, 2022)

The rate LED is supposed to light and pulsate with the LFO rate when the pedal is powered, regardless of if the effect is engaged or not.

Does the rate LED work?  Knowing that is a first good step.


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## Sparky_mark (Jan 23, 2022)

Yes the rate LED flashes when you then the pot.


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## Stickman393 (Jan 23, 2022)

Cool.  So your LFO is up and running.

Can you take voltages to ground for all pins your ICs?  Use this diagram to indicate what voltage you read at each pin #:


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## Sparky_mark (Jan 24, 2022)

Stickman393 said:


> Cool.  So your LFO is up and running.
> 
> Can you take voltages to ground for all pins your ICs?  Use this diagram to indicate what voltage you read at each pin #:
> 
> View attachment 22008


I completely forgot to reply to this, I’m really sorry!!

So the main problem turned out to be a bad MN3207, I went through the pedal testing voltages and with a audio probe but eventually started trying different chips. I must of had one bad one so now it works!

Thanks for any potential help! 
I learnt a lot about troubleshooting


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