No sound at input tip (positive ground)

[pokus]

Hey there,
something is driving me really crazy. I've built kind of a positive ground sunface clone.
No sound. Tried to find the problem with a tone probe and now there's something strange.
When bypassed there's the clean tone, but when the effect is on there's not even tone at the tip of the input jack.
How is this possible? Can't find a clear path to gnd

That's a part of my point to point layout



Thanks for any kind of help!

[patrick398]

My guess would be an error in the switch wiring rather than in the circuit. Do you have a pic of your switch?
If you've mixed up two wires you can end up grounding the input, sounds like that's what might have happened. I've been there many times.

[GibsonGM]

I try ALL effects before adding switch or LED, by using jumpers to connect a jack to in, out, the grounds incl. battery, and one for power.    Then I know if the PCB is ok without having to mess around with the switch, and if it doesn't work after adding the switch, that is the most likely error.   

Some people make a dedicated box for just this purpose, which is also great. 

[pokus]

Yeah the switch had been my first guess too, but I couldn't spot any error.

@GibsonGM sounds like a proper idea. Maybe I should have tested the board first. I think I was just getting to excited boxing it  But that's something I will definitely do in the future, as I already own such a box.

Here's my super quick layout of what's going on:

[stallik]

I think you may have that switch oriented at 90 degrees to what it should be

[pokus]

Yes, it's 90 degrees rotated, but so are the connections

[willienillie]

From your switch diagram, it should work.  Is your board IN wire green, and board OUT wire blue?  Both jack tip wires white?  Are you sure you have TRS sorted correctly?

[stallik]

My mistake. Looking at the drawing again, it appears that the ring is connected to the switch 3pdt via the on/off switch. A mono jack will short ring to ground. Also, it appears that +9v is connected to the ring via the link on the on/off switch and therefore ground

I'm looking at this on a small phone so I may have made another mistake

I'm also confused as to what the L shape link on the 3pdt is meant to achieve

[willienillie]

I'm also confused as to what the L shape link on the 3pdt is meant to achieve

It's not doing anything, but could turn on an LED if added.

[pokus]

That's exactly how I connected it. Checked it multiple times.

The pedal should connect V+ with gnd+ on the board when the input jack is plugged in, but only if the switch is on.
It's true that +9V are connected to ground(the enclosure) as it's a positive ground pedal. So I still can't see any mistake.
Right, the L shape is for adding an LED later. A looked up different wiring solutions, some have gnd connected to input when bypassed, some have not. Why?

I guess i will take this thing apart and check the board first. Can it be a faulty transistor shunting the input to ground? Actually I've tested them before, but maybe my soldering killed them, although I had put some crocos on.

[stallik]

Ah, never considered that it might be positive ground.
I had a pedal for repair once which was pos ground in which the pcb  was marked confusingly. The owner, knowing it was positive ground had connected v+ to the pad marked ground on the pcb which was incorrect. Fortunately, nothing fried

[pokus]

It's my first positive ground pedal and if I'm honest I didn't expect it to work the first time I plug it in 
I see that the gnd+ term is might confusing but couldn't think of a better way to make it clear.

I also think I've found the problem. As the pedal is very tight spaced, I didn't notice the screw, which is fixing the front panel and the board, scrapes the isolating material of the input cap. So if the input is connected to the screw, it's also connected to gnd+/+9V/enclosure. That would exactly stick to my problem not getting any sound out of the input tip.




I will try out the unboxed board and see if it's working. Do I have to replace the input cap or could it still work? 
Edit: It works!

Thank you guys for your help!

[willienillie]

Definitely replace that cap.

[patrick398]

Edit: It works!

Thank you guys for your help!

The effect works out of the box? Or that cap still works?
Either way that cap doesn't look like it's got a particularly long and healthy life ahead of it. +1 on replacing it.

[pokus]

The effect works out of the box? Or that cap still works?

Both! And it also works boxed!

I left the cap in and fixed it with a lot of tape  Now I know where to look first when there is no sound.
Also learned to give things a bit more space inside

[stallik]

You wait till you try a 1590A