Karaoke Chorus not working

[GilesYoung]

Hi! I just build this Karaoke Chorus kit (based on Boss CE-1), but it’s not really working.

I can hear it doing a chorus effect, but it’s not moving, the rate is just flat. When I turn the pots I hear the chorus, but it’s not making a chorus sound on its own.

Also, the vibrato does work, but only very fast. It doesn’t change in rate when I turn the vib rate pot, it just fades out in volume.

The rate led also doesn’t move. It’s just always bright on (on chorus and vibrato).

I soldered it as nice as I could and payed triple attention to all components that I installed.

Does anybody know where to look or what voltages I should search for etc? I can’t find a lot of trouble shooting pages about this pedal..

Thanks!

 

[neiltheseal]

You should start by checking the parts in this area. Make sure the resistors are correct (and not 220 ohm instead of 220k for example). Then check caps etc.

It sounds to me me that your lfo isn’t working so the problem will be in the area n the picture.

 

[neiltheseal]

If you could take pictures closer to the board that would be great so we can zoom in to read the stripes on the resistors.

 

[GilesYoung]

Okay thank you! Will check those things and post a picture here tomorrow.

 

[GilesYoung]

Also I noticed that the on/off led doesn’t turn off. It only gets brighter when it’s on and less bright when bypassed.

Any leads on what could be causing this?

 

[neiltheseal]

Your led is on the wrong side of the board. Usually it is on the same side as the knobs.

Led not turning off usually means there is a short. Both legs might be touching. Check the board under the led and the foot switch.

Do you have a multimeter? That can help find a short quickly

 

[GilesYoung]

I have a multimeter yes. Will check for shorts!

 

[GilesYoung]

Here are some pics.

Resistors seem fine (although I can’t measure them since they’re soldered in).

Also, the led legs aren’t touching each other (checked for short with multimeter).

 

[z2amiller]

Are you sure the backs of your pots aren't shorting anything out? They look like they're uncovered/bare metal so when they're up against the board you're going to risk shorting things out.

Have you tried adjusting the trimpots? I haven't built this specific chorus, but I have built a couple of others and they tend to have
a very narrow range on the trimpot where they produce any kind of chorus effect. (So much so that when I'm building my own
layouts I'll put in a 25-turn trimpot, or a coarse(100k) and a fine(5k) 3362p trimpot since otherwise it takes me too much fiddlin')

 

[neiltheseal]

Here are some voltages from a clone that I made. Based off the same schematic but I made my own pcb. Just the lfo and the clock bit based on your description I think your problem is here.

Maybe you could post you voltages here for all ic and transistors and we can check for you?