Loophole Vibrato Problem. Paging JakeFuzz

[jambforthelamb]

Hey all,
I've been working on a Loophole that I'm building on a Haberdasher board. I wanted to add Jakefuzz's awesome mod to it after listening to some samples. The loophole itself works great, and the detune feature works as well, I'm just not getting any vibrato. Here is the build report thread where Jake talks about his completed version of this:
http://www.madbeanpedals.com/forum/index.php?topic=2467.msg19894#msg19894
I can't seem to find the thread where he goes over the mod in detail. I guess it may have gotten lost in some of the forum drops. Fortunately I saved what I believe to be his latest version of it so I'll post that here.

My only substitution thus far is a 50k reverse for the speed pot.  I used the ISD1020, not the longer record time chip, but I would assume that makes no difference.
Here are my voltages. For the testing I had the depth pot turned fully CCW.

Source = Boss guitar 9v supply: 9.5

2n5088:
E: 5.0
B: 5.0
C: 4.3

CD4093:
1: 0.0    14: 5.0
2: 0.0    13: 4.9
3: 5.0    12: 2.5
4: 5.0    11: 2.5
5: 0.0    10: 5.0   
6: 0.0      9: 0.0
7: 0.0      8: 0.0

Thanks for any and all help 
-Kevin

[JakeFuzz]

Ahh you're right. All the most recent diagrams were lost! Ill try and repost them later today. This is the original thread:

http://www.madbeanpedals.com/forum/index.php?topic=2172.15

The diagram you have should be accurate. If the detune feature is working (and the detune pot?). There must be some kind of problem either with the CD4093 oscillator or the transistor. Just a quick glance on the CD and transistor voltages look fine (ill check closer later). Do you have access to an oscilloscope? You may want to scope out the top leg of R1 (that connects to C3) if you can.

[jambforthelamb]

Hi Jake,
Yup, detune pot works fine. No oscilloscope, just a vohm meter. Would that help at all? I've tried a different cd4093 and 5088 just to be doubly sure.
Thanks for the assistance!
-Kevin

[JakeFuzz]

Hmm, you might be able to see the fluctuations on the meter but I forget how slow the modulation rate goes. Try probing R1 and the base and emitter of the 2n5088 with the meter and set the rate to be very slow. You should see the voltage modulate a bit. It is strange that everything seems to check out as far as voltages go. I would double check the values and orientations of the caps just to make sure the oscillator is setup properly. When Pin 13 is held at 0V the oscillator is turned off. When it is held at ~5V it should output a square wave at pin 12 and 11. It looks like your meter is just taking the DC average of the square wave at pin 12 and 11. I would check those voltages at different mod rate values to see if it changes.

[jambforthelamb]

Sweet sweet success! As I was probing around I found that pins 12 and 11 were shorted together, even though I had checked that multiple times, reflowed solder, ran a straight razor through etc etc. Cleaned it up and now everything seems to be working! I need to get it boxed to really give it a good test, but it all works! Thanks so much Jake, I wouldn't have even thought to test that connection if you hadn't lead me down that path.
-Kevin

[JakeFuzz]

Awesome! Yeah that always seems to happen to me with vero board builds. Tiny shorts that are impossible to find. Helps to build debugging skills  Glad everything is working!