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DIY Stompboxes => Building your own stompbox => Topic started by: Styles on May 01, 2012, 08:56:58 PM

Title: Madbean Pork Barrel Debug Help
Post by: Styles on May 01, 2012, 08:56:58 PM
Hello again- been tearing my hair out over this- gone over the board multiple times, was convinced that I might have bought some bunk chips from a Chinese ebayer, shelled out $11 to small bear for a legit MN3007, and still no luck.  Will pass a signal when engaged, but no chorus effect through whole sweep of trimpot.  As always, help or guidance is much appreciated:

1.What does it do, not do, and sound like?  will pass signal when engaged, though no chorus effect throughout sweep of trimpot
2.Name of the circuit = Madbean Pork Barrel, w/ MN3007/3101
3.Source of the circuit (URL of schematic or project) = http://www.madbeanpedals.com/projects/PorkBarrel/docs/PorkBarrel.pdf
4.Any modifications to the circuit? n
5.Any parts substitutions? If yes, list them. C10 8.2n, sub'd parallel 6.8 & 1.5 caps
6.Positive ground to negative ground conversion? no

IC1:

1: .01
2: 2.92
3: 0
4: 0
5: 2.9
6: 0.1
7: 2.9
8: 8.9

IC2:

1: ~
2: 4.49
3: ~
4: .01
5: 4.51
6: 4.51
7: 3.5
8: 9.04

IC3:

1: 1.39
2: 1.38
3: 0.01
4: 0.01
5: 0.1
6: 0.86
7: 0.01
8: 0.6

IC4:

1: 1.39
2: 0
3: 2.01
4: 0.1
5: 1.31
6: 1.31
7: 1.38
8: .01

Q1:

c: 9.04
b: 1.87
e: 2.86

Q2:

c: 9.04
b: 2.52
e: 2.24

Q3:

c: 9.03
b: ?
e: 2.21

Q4:

c: .55
b: .58
e: .01

Q5:
 
c: 1.38
b: 1.93
e: 0.1

D1:

a: .86
k: .55

D2:

a: .68
k: .86

D3:

a: 0
k: 9.04
Title: Re: Madbean Pork Barrel Debug Help
Post by: chromesphere on May 02, 2012, 12:46:14 AM
Hey Styles.  Fustrating i know.  I'll just kick this off with the standard debugging checks.  

1) solder bridges, scratch between the tracks to make sure there are no micro solder bridges, check with magnifying glass etc.
2) Component values, check them all.  
3) Component orientation.  

These are the 3 easy ones and usually cover 99% of my issues.  If you've done all that stuff consider posting some photos of the build, top and bottom, close up.  It encourages people to help you sort out the problem.  Sort of like a Wheres Wally for the people here.
GL again,
Paul
Title: Re: Madbean Pork Barrel Debug Help
Post by: Styles on May 06, 2012, 12:18:19 PM
got this one working- needed a 33R and grabbed a 20R and a mislabeled 15k, got those switched out and it works great now.  Thanks!
Title: Re: Madbean Pork Barrel Debug Help
Post by: chromesphere on May 06, 2012, 08:21:38 PM
Awesome! Glad you got it going Styles, its a cool chorus eh!? :D

I didnt mention this but it might help you.  I made a 'how to build a guitar pedal' tutorial video series on youtube a while ago.  One of the videos is about fault diagnosing, a sort of 'crash course' in pedal fault finding and the majority of the things i do to fix a faulty build.  I've noticed your having a few troublesome builds so i thought it might help...



Anyway good luck with your other builds!
Paul
Title: Re: Madbean Pork Barrel Debug Help
Post by: Styles on May 06, 2012, 09:19:10 PM
Awesome! Glad you got it going Styles, its a cool chorus eh!? :D

I didnt mention this but it might help you.  I made a 'how to build a guitar pedal' tutorial video series on youtube a while ago.  One of the videos is about fault diagnosing, a sort of 'crash course' in pedal fault finding and the majority of the things i do to fix a faulty build.  I've noticed your having a few troublesome builds so i thought it might help...



Anyway good luck with your other builds!
Paul

awesome, thanks!