Need help with zombie chorus

[jamal]

U1(TL072CP):
P1 - 7.46(And then decreases constantly until 0, than starts again) V
P2 - 7.42(same as above) V
P3 - 0.98 V
P4 - 7.8 (Sometimes changes) V
P5 -  1.06 V
P6 - 5.22 V
P7 - 5.22 V
P8 - 8.71 V

U2(MN3007)
P1 - 8.71 V
P2 - 8.71 V
P3 - 5.22 V
P4 - 0 V
P5 - 0 V
P6 - 0 V
P7 - 6.72 V
P8 - 6.72 V

U3(TL072CP)
P1 - 4.9-5.70 V
P2 - 5.18 V
P3 - 5.1-5.34 V
P4 - 0 V
P5 - 5.18 V
P6 - 1.51 V
P7 - 5.39 - 5.42 V
P8 - 8.70 V

U4(CD4046BE)
P1 - 0 V
P2 - 4.29 V
P3 - 4.36 V
P4 - 4.36 V
P5 - 0 V
P6 - 0.93 V
P7 - 0.93 V
P8 - 0 V
P9 - 5.14 - 5.17 V
P10 - 4.27-4.30 V
P11 - 4.45 - 4.49 V
P12 - 6.79 V
P13 - 0 V
P14 - 8.69 V
P15 - 0 V
P16 - 8.69 V

[Scruffie]

Well fixing that fixed the bias issue on U1 and you also have the proper clock voltages, so something between the 3007 pins 2 & 6 and 4046 pins 2, 3 & 4 is going wrong, probably just another bad joint.

Possibly a short between pins 1 & 2 of the 3007 too seeing as they're both at supply.

[jamal]

I know get on the 4046:
P2 - 8.69 V
P3 - 0 V
P4 - 4.36 V

And on the 3007
P2 - 0 V
P6 - 0 V

Is that correct?

[jamal]

sorry, 8.68  for P2 of the 3007

[Scruffie]

No, pins 2,3 & 4 of the 4046 should be approx 1/2 supply as in your previous readings, as should pins 2 & 6 of the BBD.

[jamal]

well I'm getting kind of annoyed here. The voltages on those pins, if i move the board a little or if some minutes pass, they have the right values, but then, hey return to the wrong values

[Scruffie]

Then you probably have a bad solder joint

[jamal]

well i now get the right voltages but still no noticeable modulated sound.

[Scruffie]

I assume you're the same member debugging a zombie chorus on freestompboxes? If so as I said your BBDs are likely fake.

[jamal]

Yes I am, and i guess you are right, I just used my audio probe on the 3007 and the output sounds exactly the same as the input. That means it's a fake right? Btw, do you know if it can be replaced by a nte1641?

[flanagan0718]

Yes I am, and i guess you are right, I just used my audio probe on the 3007 and the output sounds exactly the same as the input. That means it's a fake right? Btw, do you know if it can be replaced by a nte1641?

are you in the states? If so, I have one or two I could part with.

[Scruffie]

NTE1641 should be fine.

[jamal]

Sorry flanagan, europe here. And thanks for all the help Scruffie, it was very valuable.