no bypass when powered

[jtn191]

I've been working through my slambox build and got it (mostly) working for my birthday!    LED lights up and the effect works ok, but no signal when bypassed. But it DOES bypass when the power source is removed & power drained from the circuit. It appears to have something to do with power/switching. Does this mean there's a grounding problem?

I'll see if I can figure it out, but I'd appreciate any insight. thanks!

[k.rock!]

Something that comes to mind is the main switch wiring. Are you using a 3pdt switch and true-bypass wiring? it kinda sounds to me like you may have a wiring issue.

-Kaleb

[jtn191]

yep, I'm using a 3pdt and the "general wiring diagram"

[jkokura]

Yes, there's a wiring issue. It's a strange one that I've not heard of, but yes there's a problem with the wiring somewhere in there.

Jacob

[jtn191]

I figured it was a wiring issue and was hoping someone may have an idea about the specific connection. Maybe I'm way off, but it seems like the power isn't draining out of the capacitor when switched to bypass 

[jkokura]

Take some nice pictures of it and maybe we can help.

Jacob

[jtn191]

here:



I know someone's gonna mention the mid-left lug...kinda sloppy I know

[jkokura]

I think I know what the problem is, but I could be wrong.

I think you're using isolated jacks. The right jack in the picture, your output jack, needs to be connected to ground also. The bare pins that are closes to the enclosure need to connect to ground. It may or may not fix your problem, but if you're using isolated jacks that may create the problem you're experiencing.

Jacob

[jtn191]

Hm...I did as you instructed and it did not fix the problem.

I'll try to elaborate more: when I test, I push footswitch--led and effect is working, I hit it again--no signal. I unplug the 9v dc and hit switch again. LED comes on then fades, if I hit the switch a final time--into bypass--I get bypassed signal. Could it have anything to do with the left most (in picture) lug on the dc jack and power switching?

[jkokura]

Wow. I've not seen or heard of a problem like that.

Here's the think about true bypass. It should not be affected by the power jack or the PCB whatsoever. If you do bypass properly, it should never even come into the equation. If you power and PCB is affecting the bypass signal, there is DEFINATELY a problem with your wiring.

What I suggest you do is to start over on your wiring. If you have a second 3PDT switch, I would use that. If you don't, then you need to do a search on here and learn how to carefully desolder your switch. Switches can be damaged from too much heat, so be careful. IF you have questions still, please let me know.

You could try fixing what you've got, but I think you'll learn more by trying to do it the second time, and trying to fix it may be too frustrating for you.

[jtn191]

yeah I know from first hand experience that the switch can be damaged from heat--this is my second switch.

I was just exploring with a DMM and here's a revelation: when in bypass "mode" the tip of the stereo input jack is grounded. It is also continuous with the tip of the output jack

edit: HALLELUJAH it works

here's what was wrong if anybody has a similar problem:

if the 3dpt is

1  2  3     
4  5  6
7  8  9      I had a tiny splinter of a wire acting as a jumper between 2 and 5     thanks for your patience

[bigmufffuzzwizz]

Yea even something that small will do it! Good job with the troubleshoot!

[jkokura]

Good stuff. Work on getting your soldering better and you'll experience fewer problems like that. I'm sure you'll get it if you keep with it!

Jacob

[gtr2]

Glad you got it working!  It looks like your using a non tinned copper stranded wire.  It helps when you strip the wire to tin it lightly.  This avoids random strands poking out and the wire solders more quickly to other components.  It's one of those things that helps keep things a little neater and less troublesome.   

Josh

[bigmufffuzzwizz]

Glad you got it working!  It looks like your using a non tinned copper stranded wire.  It helps when you strip the wire to tin it lightly.  This avoids random strands poking out and the wire solders more quickly to other components.  It's one of those things that helps keep things a little neater and less troublesome.   

Josh

Not to mention it keeps the strands together so they don't fray!! Ohh thats the worst.