Having trouble with my DS-1 workalike

[jman 31]

Hey guys. Great forum you have here. I have built several stompboxes, but this one has got me stumped. If anyone could look over these values for me I would greatly appreciate it.


1.What does it do, not do, and sound like?
A: It will crackle if strummed really hard. I traced it with an audio probe, and it lost most of its volume and was

distorted crackle at Q1

2.Name of the circuit =
A: Distro Uno - TL072 version (Boss DS-1 Workalike) http://www.tonepad.com/getFile.asp?id=78

3.Source of the circuit (URL of schematic or project) =
A: http://www.tonepad.com/getFile.asp?id=78

4.Any modifications to the circuit?
A: No

5.Any parts substitutions? If yes, list them.
A: No, but I tried a TL082 as a subsitute

6.Positive ground to negative ground conversion?
A: No

7.Turn your meter on, set it to the 10V or 20V scale. Remove the battery from the battery clip. Probe the battery

terminals with the meter leads before putting it in the clip. What is the out of circuit battery voltage? =
A: .001v

Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to

turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal

ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have

a plug in it. With the negative lead on signal ground, measure the following:

Voltage at the circuit board end of the red battery lead =
A: 8.36v

Voltage at the circuit board end of the black battery lead =
A: 0.00v

Now, using the original schematic as a reference for which part is which (that is, which transistor is Q1, Q2, etc.

and which IC is IC1, IC2, C1, and so on) measure and list the voltage on each pin of every transistor and IC. Just

keep the black lead on ground, and touch the pointed end of the red probe to each one in turn. Report the voltages

as follows:

Q1
C = 8.35v
B = .21v
E = .00v

Q2
C= .82v
B= .63v
E= .03v

Q3
C= 8.35v
B= .33v
E= .03v

IC1 (or U1)
P1= 1.36v
P2= 1.36v
P3= .86v
P4= 0.00v
P5= 1.35v
P6= 1.36v
P7= 1.38v
P8= 8.34v


D1
A (anode, the non-band end) = .21v
K (cathode, the banded end) = .21v

D2
A = .21v
K = .21v

D3
A= 0.00v
K= .86v

[oskar]

Hey guys. Great forum you have here. I have built several stompboxes, but this one has got me stumped. If anyone could look over these values for me I would greatly appreciate it.

Hey yoursef and welcome!
I'll try and help you. Ok, I didn't read any further than to the first lines. The battery connected is 8.36 which is a bit low and the battery voltage out of the unit is.... nah... 0.001V not likely!      take out the battery and give us a new reading.

1.What does it do, not do, and sound like?
A: It will crackle if strummed really hard. I traced it with an audio probe, and it lost most of its volume and was

distorted crackle at Q1

Q1
C = 8.35v
B = .21v     <---                 wrong!
E = .00v

Q2
C= .82v
B= .63v      <---                 right!
E= .03v

Q3
C= 8.35v
B= .33v      <--                     wrong!
E= .03v

Schematic top left:Two 10k resistors and a 47uF cap. Please measure Vb which is a reference voltage at the cap. Put the black probe/com at ground and the red probe at the cap/resistor crossing. It should read ~4.5V

[jman 31]

Thanks for your help! The 47uF cap was bad. (or maybe it was in backwards, I'll never tell ) Fixed and works great. Thanks Oskar!!!!

[oskar]

Wow. That was quick! Great!!!