Cepheid chorus stopped working

[MrTambourineMat]

Hello everyone, a month ago I finished a Cepheid chorus, I had a problem in the first place but I solved it thanks to this thread.


Now I have a new problem: the pedal has worked for one month but yesterday it started to make noise when turned on, but not every time. It also makes “the click” (idk how to call it) when I turn it on.
The effect works but it’s not as good as before, it’s kind of distorted. I’ve tried to turn the trimmer but the problem persists (actually if I turn it too right or too left it make this sound).
Then, I don’t know if there could be a relation (because I hadn’t used the pedal for like a week), but yesterday was the first time that I used my active bass with a 18v output through the pedal.

Any suggestion?


Here there are all the measurements, thank you in advance:

TL022CP:

1. Variable (1-7V)
2. 1/2 Vcc (4.3V-4.5V) - not stable
3. Variable (3-6V)
4. 0V
5. 1/2 Vcc (4.3V-4.5V) - not stable
6. 3.14V - stable
7. Variable (3-5V)
8. Vcc

MN3101:

1. 8.90V
2. 4.57V
3. 0V
4. 4.61V
5. 0.20V
6. 8.05V-8.15V
7. 2.90V-3.06V
8. 0.59V

MN3007:

1. 8.88V
2. 4.60V
3. 4.84V
4. 0.59V
5. 0V
6. 4.57V
7. 4.50V
8. 4.50V

RC4558P:

1. 5.61V
2. 5.62V
3. 5.50V
4. 0V
5. 5.55V
6. 5.62V
7. 5.61V
8. 9.02V

 

[jwin615]

Does it only distort with the active bass?
It's output could simply be too hot to handle.

 

[MrTambourineMat]

Hi, no I’ve tried it also with a passive guitar and it has the same problem. Is it possible that something fried up because of a too hot output?

 

[music6000]

Just to Confirm, Did you power the pedal with 18v?

 

[MrTambourineMat]

Sorry, I’ve just read the message…

I thought I fried something of the pedal connecting a bass that has a 18v active circuit, but it should be impossible (right?).

The pedal has always been powered with 9V.

By the way, now the pedal does not work at all (if I play hard I can hear something that sounds like a low volume distortion) and it smells bad. I’ve made a new measurement and those are the results, the MN3101 and the MN3007 seem to be powered with reverse polarity.
I cannot understand why, they are placed right and the others two chips (TL022CP and RC4558P) seem to be powered right.

Edit: if I move the MN3007 or the TL022CP the pedal start working with some noise, I’ll check the welds…


TL022CP:

1. Variable (2-6V)
2. 1/2 Vcc (4.4V) - not stable
3. Variable (2-6V)
4. 0V
5. 4.35 - not stable
6. 3.53V - stable
7. Variable (3-5V)
8. 8.91

MN3007:

1. 8.91V
2. 4.64V
3. 4.01V
4. 0.59V
5. 0V
6. 4.60V
7. 3.65V
8. 3.65V

MN3101:

1. 8.92V
2. 4.64V
3. 0V
4. 4.64V
5. 0.21V
6. 8.03V
7. 2.90V - not stable
8. 0.59V

RC4558P:

1. 4.78V
2. 4.79V
3. 4.68V
4. 0V
5. 4.73V
6. 4.79V
7. 4.78V
8. 9.05V

 

[Bio77]

Given the time lag to problem, I would check your transistors. They might have come loose from those sockets.