Informant Overdrive - No Signal (Buffer or Effect)

[YakSabbath]

Hello! I am currently working on an Informant Overdrive but ran into a snag – LED works but I have no signal through the pedal on buffered or effect mode.

Strangely I am getting 17V on the second opamp but not the first, I have switched the chips around with same results to it must be circuit related, see voltages below:

IC1

1 - .01V

2 - .01V

3 - 7.22V

4 - 0V

5 - 7.22V

6 - 0V

7 - 0V

8 - 0V

IC2

1 - 8.81V

2 – 8.8V

3 – 7.22V

4 – 0V

5 – 7.22V

6 – 8.8V

7 – 8.84V

8 – 17.52V

IC3

1 – 9.1V

2 – 4.56V

3 – 0V

4 - 0.17 V

5 - 0.38V

6 – 4.38V

7 – 6.81V

8 – 9.1V

I seem to be getting noise floor – the volume and drive controls give proportional noise when dialed up and down, cut control seems to filter the noise, seems like the latter section of the circuit is functioning but no signal getting through IC1

Using a MAX1044 for voltage charge pump with bead of solder across jumper pad as per instructions, I have tried two different chips with same results

Picture attached of back and front of board attached, i have reflowed twice already

Any help would be appreciated – thanks!

 

[YakSabbath]

Further to this, I have used an audio probe and the signal stops in opamp 1 (obviously - there’s no voltage)

I pulled ICs out and read NO continuity between pin 8 on each (as per schematic they should be in parallel with each other)
On underside of board I put a jumper lead between solder pads in case of a bad trace and now I get continuity, however I still have NO opamp voltage on IC1! Is there a bad capacitor somewhere in the supply side messing things up?? Is the opamp socket faulty??

 

[music6000]

Further to this, I have used an audio probe and the signal stops in opamp 1 (obviously - there’s no voltage)

I pulled ICs out and read NO continuity between pin 8 on each (as per schematic they should be in parallel with each other)
On underside of board I put a jumper lead between solder pads in case of a bad trace and now I get continuity, however I still have NO opamp voltage on IC1! Is there a bad capacitor somewhere in the supply side messing things up?? Is the opamp socket faulty??

Have you tried swapping Op Amp's?

 

[fig]

Maybe add C105 positive side?

No fig, because the other TL072 is getting current, so C105 has to be okay.

Sorry, having a heated discussion with myself here. Just ignore me and carry on.

 

[music6000]

Have you tried swapping Op Amp's?

Test for Continuity on all these Red Circles :

UPDATE : They should all be receiving around 18 volts!

 

[fig]

Let's play rock, paper, scissors until they come back!

Go!........what'd you get?

 

[music6000]

Let's play rock, paper, scissors until they come back!

Go!........what'd you get?

Always Rock!
The Pin 5 Solder pad looks suspect on the Bottom TL072 ????

 

[music6000]

Always Rock!
The Pin 5 Solder pad looks suspect on the Bottom TL072 ????

See, I was testing you this time, I t was really Pin 5 that looks Suspect!!!

 

[YakSabbath]

It suddenly decided to start working on its own, thanks everyone for the input!

And holy wow this pedal sounds AWESOME!

 

[music6000]

It suddenly decided to start working on its own, thanks everyone for the input!

And holy wow this pedal sounds AWESOME!

Well hopefully it suddenly doesn't decide not to on its own!!!

 

[nichgriff]

Test for Continuity on all these Red Circles :
View attachment 16842
UPDATE : They should all be receiving around 18 volts!

Test for Continuity on all these Red Circles :
View attachment 16842
UPDATE : They should all be receiving around 18 volts!

Should there be continuity at all of these places?