Debugging Skreddy P19

[IbanezRG95]

I have built the Skreddy P19 on vero using the layout at http://tagboardeffects.blogspot.com.au/2012/05/skreddy-p19.html

The bypass works. However, when the effect is engaged, there is no sound, at any rotation of the potentiometers.

I have made no modifications to the layout and no part substitutions.





The voltages for the parts (labelled as per the layout) are as follows:

Q1
C = 0.86
B = 0.80
E = 0.18

Q2
C = 0.86
B = 0.80
E = 0.18

Q3
C = 0.85
B = 0.80
E = 0.18

Q4
C = 7.28
B = 8.01
E = 7.28

Dx
A = 9.45
K = 9.22

D1
A = 0.67
K = 0.80

D2
A = 0.80
K = 0.67

D3
A = 0.80
K = 0.67

D4
A = 0.67
K = 0.80

If anyone could point me in the right direction, this would be greatly appreciated.

[IvIark]

The transistors need turning round

[IbanezRG95]

turned the transistors round - still no sound.

on a side note, wouldn't the pedal still produce a faint sound if the transistors were round the wrong way (with the base still in the middle)

[Pyr0]

Not necessarily.
If you used BC550's they are certainly orientated wrong in your photo.
I always ignore the vero layout orientation for transistors and look up the datasheet to find the correct pins.

What are the voltages now that you have turned them around ?

[IbanezRG95]

Pretty much the same @

Q1
C = 0.81
B = 0.80
E = 0.18

Q2
C = 0.81
B = 0.80
E = 0.18

Q3
C = 0.81
B = 0.80
E = 0.18

Q4
C = 7.27
B = 8.01
E = 7.26

[Pyr0]

I'm not sure if it's just the colour in the pics, but to me it looks like all your 470k resistors are actually 470 ohms.
That would certainly cause problems.
Just looked at the schematic for this, those 470k resistors are between base and collector of Q1, Q2 & Q3, so if they are only 470 ohm, it would explain those weird voltages.

[IbanezRG95]

They are only 470 ohms 

Thats the last time I will go by what value futurlec has written on the bags of resistors.

Thanks a ton for checking over that pyro.

[Pyr0]

No bother mate.

Hints:
1 - Learn the resistor colour code.
2 - Always check resistor values from a new batch with your DMM before putting them in the appropriate drawer.

I've been caught out a few times with resistors mis-labeled, it's a bitch to debug once they are in place.

Hope you get this working.

[morrissey007]

Bit late in the day but I think you've missed the long link that joins the top and bottom ground strips together? There should be 5 links I only counted 4 on your board. And the Transistors are definitely the wrong way round. Hope you got it working?