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Slap Chop, not chopping :/

Started by Mike @ Rawkworks, February 16, 2011, 03:31:41 PM

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Mike @ Rawkworks

 So the effect passes signal in bypass mode, but when I switch it on the signal goes as far as R5 and stops. I've replaced this resistor and still nothing. Any suggestions would be greatly appreciated, has this happened to anyone else?
Mike
mike@rawkworks.com

CRBMoA

What does C-3 look like? It is an electro, and the - leg (usually indicated by a black strip on the body of the cap) should be on your left as you are looking down on the board as shown on the project page.

jkokura

Do you think he might mean the other side Chris? He didn't mention which side, but I instantly thought he meant on the 'south' side.

If you mean the side of R5 that's also attached to the middle lug of Q1, it might mean that Q1 is either improperly soldered or may be turned the wrong way. Did you double check the pinout of your transistors against the schematic and layout? It may be that you need to turn that transistor around.

I also just noticed that this is a Buffered effect, meaning that it's not supposed to be True bypassed. What did you do when wiring the circuit? Because if you didn't wire it correctly it may not work properly.

If I read the schematic right, once you turn the effect on the effect HAS to go through R5, then C3, and then into the IC. If you have wired the pedal correctly according to the diagram in the documentation, and you have signal between R5 and C3, but none after C3, the problem may also be that you have a bad capacitor. If you have no signal between R5 and C3, it may mean you have a bad resistor.
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

Mike @ Rawkworks

Thanks for the responses, I know this effect will work. It has to be something simple.

I've wired it according to the pdf and played it pretty much by the books except for the 5k pot, im using a 10k.

I re-touched the transistor joints with my iron as well as R5. I can follow the signal with an audio probe until the south side of R5, but the on the other side, no sound. The resistor is showing 22k on my multimeter, as did the first one, so I don't think its that.

The IC looks like this
1 - 3.76
2 - 3.76
3 - 3.74
4 - 7.52
5 - 3.76
6 - 3.76
7 - 3.76
8 - 3.76
9 - 3.76
10 - 3.76
11 - 0
12 - 3.74
13 - 3.76
14 - 3.76

          /--0
Q1 - (|--1
         \_7.52

         /--7.52
Q2 - D--8
         \__8.6

I'm gonna keep pondering and I'll let yall know what I come up with. Thanks again
Mike
mike@rawkworks.com

jkokura

Replace R5, or resolved it connections and it might help. There must be sound on the other side, and the only thing I can see is that R5 needs work.

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

Mike @ Rawkworks

Minor progress! Still works fine in bypass mode, but now I can barely hear signal coming thru! Turning the pots also seems to effect the sound (but its very quiet so hard to tell)

I replaced R5 and changed the IC. Same voltages for the new IC. Back to the bench...
Mike
mike@rawkworks.com

Mike @ Rawkworks

Frustrated Inc.

After weeks of failure,I'm giving up. I've tried just about everything (changing transistors, swapping transistors, audio probing, changing to a DPDT, measuring/posting voltages, changing chips, powering with 1Spot/9volt/Boss adapter, resoldering, looking over traces again and again, etc.)

Has anyone gotten this thing to work?
Mike
mike@rawkworks.com

CRBMoA

Totally. It is a fantastic circuit. I built one by request for a friend, and was blown away.

So much so, that I ordered a board for myself.

Good clear pics, front and back, would allow us to see what is going on. It is a pretty straight forward circuit, but EVERYONE can use an extra set of eyes from time to time.

Chris

Haberdasher

I built one too and it works fine.  Something is still not quite right on yours.
I agree that you should post some pics.  Someone may spot something, who knows.
Looking for a discontinued madbean board?  Check out my THREAD

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Mike @ Rawkworks

Here are a few shots, best I can do with my camera I believe...

I may just wind up buying a board after trying again, I want this one bad!

[attachment deleted by admin]
Mike
mike@rawkworks.com

Mike @ Rawkworks

And number 4

[attachment deleted by admin]
Mike
mike@rawkworks.com

Mike @ Rawkworks

not pretty I know, the black stuff if left over toner that stained the board. out of curiousity, could I just bypass the buffer part?
Mike
mike@rawkworks.com

Mike @ Rawkworks

WE WON!

Due to my poor eyesite I typically blow up the layout portion of project. This one in particular had R6 and R8 looking very similiar and due to their positions I switched them. Works great now!!

PS-I have another one half way finished (noticed the err of my ways when I got to those resistors)...can anyone say "Its gut a volume pedal time?"

Thank you to all who gave suggestions!!
Mike
mike@rawkworks.com

bigmufffuzzwizz

Great job finding the problem!! Now how does it sound?  ;D
Owner and operator of Magic Pedals

Mike @ Rawkworks

Pretty neat, works great with other effects. I haven't been able to try all combinations but one cool one so far was to put it in front of a Wolfshirt with the octave on. Pretty outrageous sounds!
Mike
mike@rawkworks.com