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 Post subject: Lazy Sprocket Build
PostPosted: Sat Jul 29, 2017 4:41 pm 
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Joined: Sat Jul 29, 2017 4:34 pm
Posts: 4
Hello, I just finished building my lazy sprocket build, however I am having some difficulties. I own [for refrence], a function generator with square waveAM modulation that I can use to test the attack, an oscilloscope, a DMM, and a bench power supply.
The pedal works in bypass, but when I turn it on there is complete silence. Additionally, the voltage between the input and ground stays at 0 when on.
I have looked around on previous posts and have tested the OP amp pin 3 and do not see my signal there and I have tested op amp pin 6 and it stays at a constant 4.6V. This is independant of knob or trimpot position. But I think the big issue here is that my signal across the input jack dissapears when the pedal is on.
Shorting the tantalum cap gives me full signal in the output.
Do you have any recommendations for test points, either for DC voltages or for signal? Does anything pop out to you immediately? Thanks!

Here is my circuit board, a few notes
I was missing a 47nF cap so I soldered 2 22nF caps in parallel
I had a very hard time attaching the purple wire into S2, so I soldering the purple wire into a white, solid core one

https://imgur.com/a/Htlq4


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 Post subject: Re: Lazy Sprocket Build
PostPosted: Mon Jul 31, 2017 11:11 am 
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Joined: Sat Jul 29, 2017 4:34 pm
Posts: 4
Bump


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 Post subject: Re: Lazy Sprocket Build
PostPosted: Mon Jul 31, 2017 12:42 pm 
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Joined: Tue Jan 02, 2007 1:24 pm
Posts: 16196
Location: Albany, NY
I strongly suspect your problem lies in the poor quality of your wire connections to the jack, footswitch and PCB. I see blobby and irregular solder joints, lots of exposed wire between the end of the insulation and the solder joint, and stray strands of wire and protruding wire ends. Personally, I would tear out the wiring between the jacks, footswitch & PCB (leave the pot wiring for now), clean up the various connection points and re-wire the pedal. There are some good pointers on good wiring practices at these links:

viewtopic.php?f=9&t=6401

viewtopic.php?f=50&t=33293

You may also want to look through this post for some other ideas on what to do when you get signal in bypass but not when the effect circuit is engaged:

viewtopic.php?f=9&t=52188

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2


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 Post subject: Re: Lazy Sprocket Build
PostPosted: Mon Jul 31, 2017 1:02 pm 
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Joined: Sat Jul 29, 2017 4:34 pm
Posts: 4
Thank you for the advice, I will take a closer look at those wirings over the next few days. I will replace the long wires with shorter ones and reflow some solder. I did have difficulty with them as this is my second build [the ESV Germanium fuzz was much easier and works great!]. I'll let you know how it goes. I will also probe around for continuity. I think that although the jacks do look messy I doubt they would be the root of the problem since I get signal in bypass and LED turns on, so the pedal is getting power.
I'll also reflow the joints on the PCB itself. Are there any specific areas I should be looking at if shorting the tantaulm cap gives me signal? I assume then that the problem is in the envelope detection somewhere which might be the sensitivity pot honestly.


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 Post subject: Re: Lazy Sprocket Build
PostPosted: Mon Jul 31, 2017 1:19 pm 
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Joined: Tue Jan 02, 2007 1:24 pm
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Location: Albany, NY
jshakes213 wrote:
I think that although the jacks do look messy I doubt they would be the root of the problem since I get signal in bypass and LED turns on, so the pedal is getting power.

I would agree with that. But if you're cleaning up other parts of your wiring, I'd re-do those, too. Could prevent future problems if any of those joints are weak.

jshakes213 wrote:
I'll also reflow the joints on the PCB itself. Are there any specific areas I should be looking at if shorting the tantalum cap gives me signal? I assume then that the problem is in the envelope detection somewhere which might be the sensitivity pot honestly.

That's an interesting observation. I'd be looking for any evidence of shorting (solder bridging, splash or a stray wire strand) between adjacent solder joints not already connected with a board trace. BTW, how did you physically short the tant?

Would also be useful to get DC voltage readings on the IC.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2


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 Post subject: Re: Lazy Sprocket Build
PostPosted: Mon Jul 31, 2017 10:23 pm 
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Joined: Sat Jul 29, 2017 4:34 pm
Posts: 4
Reflowed all my joints and the pedal works like a charm now. thank you for your help!


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