Faultline Fault

[Guybrush]

Hey there

I've just finished putting together a Faultline and run in to an issue that I can't get to the bottom of.

The circuit worked perfectly when hooked up to my test rig but when I boxed it up I just get a nasty buzzing when the effect is engaged and no sound at all in bypass. Also when I press the switch to turn the effect on the LED lights for a split second then goes out.

I've replaced the DC jack, 3pdt and the jack sockets but the problem persists. Hooked it back up to my test rig and everything is fine so it's definitely a problem with the offboard stuff.

One thing to note is that the Faultline circuit has the LED wired to the board (rather than offboard like in the standard wiring diagram), I've connected the SW pad to the top left lug of the 3pdt as instructed. 

Can anyone help?

Here is a photo of the switch and a short video that will hopefully help.

https://youtu.be/h5rDxV5xtcw



Thanks guys.

[lincolnic]

The circuit worked perfectly when hooked up to my test rig but when I boxed it up I just get a nasty buzzing when the effect is engaged and no sound at all in bypass. Also when I press the switch to turn the effect on the LED lights for a split second then goes out.

It sounds like you've got either a cold solder joint on a ground point somewhere (3PDT maybe?), or power might be shorting to ground in your box. Since you said you've already swapped all the hardware around, it seems unlikely (though not impossible!) that you'd have the same cold solder joint in the same spot. I'd try reflowing all your ground connections.

You should also take a closer look at the pedal once you have it boxed up and see if you can spot any shorts - use your DMM to check for continuity.

[Guybrush]

Thanks for the suggestions, I'll give them a try tonight. 

Other than on the 3pdt, DC jack and pcb where are the other ground connections? Sorry if that's incredibly stupid. Just don't want to miss any!

Thanks again.

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[muddyfox]

I normally ground at least one I/O jack.

[Guybrush]

I normally ground at least one I/O jack.

Please could you describe how this is done? I normally just follow Madbean's standard wiring diagram. When someone says "make sure the X,Y or X is grounded" I don't really know what this means.

I know that this is an incredibly basic question but it's a hole in my knowledge and something that's bothered me for a while.  Thanks.

[twin1965]

I always ground the input jack. I connect all my grounds to that jack. If you are using a painted enclosure make sure that the sockets are making full contact with the bare aluminium. Otherwise the paint acts as an insulator and they won't be grounded.
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[Guybrush]

I always ground the input jack. I connect all my grounds to that jack. If you are using a painted enclosure make sure that the sockets are making full contact with the bare aluminium. Otherwise the paint acts as an insulator and they won't be grounded.
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Please can you explain "all my grounds". There is obviously one coming off the PCB but that is connected to the 3pdt. How can it be also connected to the in jack? Just run a wire from the 3pdt lug to the socket? Where are the other grounds?

Th enlosure is envirotexed but is bare aluminium on the inside so this should be ok right?

[muddyfox]

I normally ground at least one I/O jack.

Please could you describe how this is done? I normally just follow Madbean's standard wiring diagram. When someone says "make sure the X,Y or X is grounded" I don't really know what this means.

I know that this is an incredibly basic question but it's a hole in my knowledge and something that's bothered me for a while.  Thanks.

I dont use the madbean diagram (not that there's anything wrong with it), I use Mark's here:


It grounds both jacks just for kicks. It's the black wire that connects the board ground, dc negative pole and one or both i/o jack sleeves. This gives you a common potential that you can call "ground".

[midwayfair]

Where are the other grounds?

"Ground" is kind of a bad name for what we're talking about. A better way to think of it is "common." What are the things that must be connected all the time for the stompbox to work?

1) The sleeves of the in/out jacks (this is the shielding on the guitar cable, and the "negative" from our pickups is carried on it).
2) The enclosure, to ensure good shielding.
3) All ground points in the schematic. Not sure if something's supposed to connect to ground? Check the schematic.
4) The DC jack's (and battery's) ground connection.

The reason we typically only have to ground one in/out jack sleeve is that if we're using metal jacks and a metal enclosure, they'll be connected to each other just by both touching the enclosure.

As for the off-board wiring, it's pretty well explained in here: http://www.madbeanpedals.com/tutorials/downloads/StandardWiring_MBP.pdf

[Guybrush]

Thanks guys that really helps.

I always use the Madbean wiring diagram and have never had a problem (as far as I remember) with things going wrong with the off board wiring. Therfore I'm almost certain it's not a grounding issue (especially as I have replaced all the hardware).

As I previously mentioned the Faultline circuit has the LED wired directly to the board (rather than the standard offboard). As the pedal works when hooked up to my test rig I'm going to try attaching an offboard LED and just forgetting the onboard one. The LED on my test rig works with the circuit hooked up so I think this should do the trick.

Thanks for all the help and explanations. Greatly appreciated!

[lincolnic]

I'm not sure that the LED is causing your problem. If it works on your test rig but not in the box, then the problem has to be either with the hardware, the wiring, or the physical layout of the box. Since you've swapped out all the hardware (and therefore redone the wiring) already, my guess is that something is shorting out against the enclosure. Is the PCB getting pressed against anything? If so, did you try covering the solder side of the board with electrical tape?

[Droogie]

Are you using open frame jacks? I've had them ground on the enclosure if I drilled the holes for them too close to the top. When the cable is inserted, there is quite a bit of play on the tip connector.

[Guybrush]

I've not put the lid on yet so it's not the jacks shorting.

I've has a bit of progress. I've done a bit of reflowing and I'm now getting sound in bypass.

So to recap and update. The circuit works perfectly when on my test rig. When I wire up the off board stuff and box it up I get sound in bypass but when I press the 3pdt I get a split second of sound LED light before it goes out and the sound dies.

I've tested continuity between ground points and all is well.

Anyone got any other suggestions? I'm on the verge of throwing it out of my 15 storey window!

Thanks for all the help so far.

Edit: Fixed it. Reflowed everything and then worked out that the 3pdt was somehow shorting when I tightened it up. Thanks again for the help. One day I'll be able to figure this stuff out myself!

[lincolnic]

Glad you've got it figured out!

Don't feel bad about asking for help. This is how you learn - the only reason I knew to make the suggestions I made is that I ran into similar problems and asked here for help. The more problems you run into, the more problems you know how to solve the next time they happen.

[twin1965]

Good that you sorted this out. I've had issues with 3pdt switches before. PITA!

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