SOLVED Cepheid Chorus no effect (TB and LEDs working)

[MrTambourineMat]

Hello, I just finished to build a Cepheid chorus, I bought a kit from DasMusikding because I wasn’t able to buy just the PCB (I’m from Europe), so I presume that the MN3007 is original.
True bypass and both LEDs work fine, but when I turn the effect on it does nothing, I’ve tried to turn the trimpot and if I got too much off the center, both clockwise and CCW, I stop hearing the clean sound and start to hear something that seems a white noise with chorus.
I’ve double checked the board and everything seems to be fine. Any tip?
Thank you

 

[MrTambourineMat]

Here’s a short video of what I mean:

 

[Bio77]

One of your transistors appears to be in backwards.

 

[Erik S]

The transistor orientation looks correct to me with all the flats pointing down. I wasn’t able to spot any component errors.

 

[jimilee]

What do your voltages look like? Have you reflowed everything?

 

[chris.knudson]

One of your transistors appears to be in backwards.

I initially thought the same thing, but I think they're in right. I do suspect the transistors though.

 

[chris.knudson]

You might want to check your resistor values. R33 doesn't look right to me.

EDIT: I think I read it backwards -- might be right after all.

 

[MrTambourineMat]

Thank you all for the answers.
1) I’ve checked all transistors and to me they seems to be in the right position. All “facing” down with this sequence of pin: EBC.
2) Checked out voltages and the MN3007 has like 8.7V, shouldn’t it be between 10-15V? (I’m powering up the pedal with a 9V power supply)

P.s. Maybe I’ll try to clean again the bottom part of the PCB, can I use isopropyl alcohol right?

 

[MrTambourineMat]

Here there are some photos of the bottom part

 

[synthesiserror]

These are the pads for your board power. Are these joints touching each other?

 

[MrTambourineMat]

These are the pads for your board power. Are these joints touching each other?

View attachment 66024

Just tested with a multimeter, they are not touching

 

[MrTambourineMat]

Here there are all the measurements:

TL022CP:

1. Variable (1-7V)
2. 1/2 Vcc (4.3V) - not stable
3. Variable (1-5V)
4. 0V
5. 1/2 Vcc (4.3V) - not stable
6. 2.76V - stable
7. Variable (2-6V)
8. Vcc (8.71V)

MN3007:

1. 8.71V
2. 4.23V
3. 3.70V
4. 8.15V
5. 0V
6. 4.21V
7. 6.23V
8. 6.20V

V3102D:

1. 8.71V
2. 4.23V
3. 0V
4. 4.23V
5. 0.15V
6. 8.53V
7. 2.80V - not stable
8. 8.53V

RC4558P:

1. 4.43V
2. 4.43V
3. 4.34V
4. 0V
5. 4.38V
6. 4.44V
7. 4.44V
8. 8.83V

 

[synthesiserror]

I'm not sure the V3102 and the MN3007 will work together. I could be wrong. I used a V3102/v3207 in mine.

 

[Bio77]

I'm not sure the V3102 and the MN3007 will work together. I could be wrong. I used a V3102/v3207 in mine.

3007 needs a 3101

Thank you all for the answers.
1) I’ve checked all transistors and to me they seems to be in the right position. All “facing” down with this sequence of pin: EBC.
2) Checked out voltages and the MN3007 has like 8.7V, shouldn’t it be between 10-15V? (I’m powering up the pedal with a 9V power supply)

P.s. Maybe I’ll try to clean again the bottom part of the PCB, can I use isopropyl alcohol right?

Sorry about the transistor comment. There is a trace near the bottom right transistor I thought was the transistor outline.

 

[synthesiserror]

3007 needs a 3101

That's what I thought.

 

[MrTambourineMat]

Ouch, thank you!
I didn’t notice that, I’m gonna order that clock and I’ll let you know. Thank you so much.

 

[synthesiserror]

Ouch, thank you!
I didn’t notice that, I’m gonna order that clock and I’ll let you know. Thank you so much.

Cabintech has a new-production 3101 replacement. I don't know about their availability in Europe.

Cabintech Global LLC

Specialty analog and digital audio semiconductors, synthesizer, and guitar effects modules from Coolaudio, Xvive, Alfa Rpar, and others

cabintechglobal.com

 

[MrTambourineMat]

Hello everybody, good news. Today I received the 3101 and I’ve just replaced the 3102 with it.
It works!

Thank you very much!

 

[synthesiserror]

Save the 3102 and build the Caesar next!