So I built my first pedal (a form of distortion pedal), and the circuit I perfboarded works perfectly on its own. However, when I try to put the board in an enclosure, something seems to be shorting. It only works if I leave the board hanging out of the enclosure in a certain manner, otherwise it just cuts out. I have been thoroughly examining all of my solder points and I don't see anything that is obviously shorting or any conductive bits that are moving when I move the board. Is there a good way to go about figuring out what is shorting, or am I just going to have to take everything out and try again?
Happens to me frequently, especially when I'm trying to use a small box. Something is shorting. Could be against the box, could be components getting pressed together on the board, pot lugs, etc etc. if you suspect that you're shorting against part of the box, you can line part of the inside with a piece or two of electrical tape. I've also thrown a small piece over a jumper on my board when I found that a transistor was bending over it and shorting out. Be patient, you'll find it!
1) If you have any vertically mounted resistors, the leads can sometimes short out against pots.
2) When tightening nuts , one can sometimes unintentionally rotate pots so that solder lugs short out against the chassis or nearby pots. I like to use a small piece of heat-shrink tubing to insulate solder lugs (including lugs I don't use), as well as provide a bit of strain relief. A bit of extra effort, but it neatly sidesteps the shorting-out problem and saves a heap of time in torubleshooting. Just make sure the solder joint is good before covering it up, because you won't be able to see a loose wriggling wire once the heat shrink covers it.
3) Iy you are using phone jacks with exposed solder lugs, make sure they are rotated to be safely out of the way. I use small pieces of heat shrink tubing to cover them as well.
Have you got something between the board and the base of the box?
I glue cushioned foam on the underside of the box lid.
If it works hanging out of the box it should work inside too unless like you say its shorting or a fractured wire or some such.
someone whos better than me im still a newbie will come along and offer you some good advice soon.
I hope you get it sorted
Rich
It's quite likely that it is a grounding issue due to jacks for the input, output or power being the wrong way around.
Without any power, check the outer ring of any jacks and make sure there's zero resistance between the outer part (that is in contact with the enclosure) and the ground for the circuit board. You can do this easiest with the circuit out of the enclosure. Other than that, I like to insulate the inside of the enclosure with plastic/stickers/electrical tape just to be certain.
Let me know if you get anywhere with that!
take some pictures if you can't solve the prob....
bad solder perhaps. if u need to position board somehow in order to get it to work. check solders of wires
Wow, thanks for all the responses so far.
I think what I am going to do is insulate everything I can with electrical tape. This will also force me to examine all the solder joints and see if I missed anything funky. If I still can't get it working, I will be back with pictures.
Now that I think about it, it is a little funny that we stick circuits in conductive enclosures.
It actually makes a lot (http://en.wikipedia.org/wiki/Faraday_cage) of sense. (http://en.wikipedia.org/wiki/Electromagnetic_shielding)
Oh of course, how silly of me to forget Faraday cages. I guess I am blinded by my struggle at hand.
An alternative to electrical tape is the flat parts of plastic containers, eg., strawberry containers; cut the flat parts so they fit inside the pedal enclosure, and just lay them in there after cutting out the holes for the switch.
It seems I found my issue, it's the volume pot. If I remove the pot from the circuit (in the pictures, that is just soldering the red wire to the green one), there seems to be no issues. When the pot is in the circuit (the whole thing is outside of the enclosure), it will only work when it is situated just so, but I don't see anything that might be shorting.
Pictures of pot in question:
http://imgur.com/a/3vvFz (http://imgur.com/a/3vvFz)
Excellant have fun. :)
Quote from: Kipper4 on June 11, 2013, 11:31:24 PM
Excellant have fun. :)
Well I still need to figure out the issue with this pot, otherwise I am very quickly going to blow out my eardrums.
Test with another same - I'm going to go out an suggest the pot is faulty.
EDIT: Now I'm going to go silently sit in the corner as punishment for not reading the symptoms correctly prior to posting.
It appears in the photos that you've soldered your wires through the side of the lugs that face the enclosure. When you tighten the nut on the pot, you may be forcing one or more of the exposed wire or the lugs against the enclosure.
The other possibility is that when you install the pot, a wire on one of the lugs is being pressed back toward the pot's metal case and shorting against the case, which is electrically connected to the enclosure.
I recommend inserting your wires from the back side of the pot and after they are soldered, snip of anything that might be protruding toward the front of the pot, which is where the enclosure will be.
I missed this photo the first time:
(http://i.imgur.com/hNIZTJSh.jpg)
Either the red wire is grounding out against the enclosure or the black wire is being pinched against the metal case of the pot.
Try the back door method and see if that helps. ;)
BTW, unless you've drilled a key hole for that knub on the pot, it's going to ride at an angle in the enclosure. You can snap it off with a pair of pliers.
this may not need to be asked but.. is there a bridge wire connecting the ground side of the pot to the base of the pot, or any wire connecting the pot base to Ground?
you might try connecting a wire to circuit ground, and then touching the body of the pot w/ other end. if you lose signal/output, it's yr pot connections shorting.
Quote from: Thecomedian on June 12, 2013, 03:26:33 AM
this may not need to be asked but.. is there a bridge wire connecting the ground side of the pot to the base of the pot, or any wire connecting the pot base to Ground?
No, the base goes directly to the output jack and ground goes to ground (theoretically, there might be a short somewhere that I have yet to discover)
Avoid soldering your wires into those little holes on the pot. Use the tabs instead. When you heat up the metal in those holes, they expand and very often you loosen them enough to screw up continuity. It's possible that mounting the pot in the enclosure is causing enough pressure on those wires to break the connection. Try pushing on those connectors with the pot outside of the enclosure. If the signal cuts out, replace the pot and you're done. Once continuity is compromised you usually can't rescue the pot.
I think that was the issue. I replaced the pot, and while this one still gets a little finicky when i move it around (I would expect so), it seems a lot more stable than the old one. Now, that little metal tab is being a real pain, but I am sure I will get it off.
Quote from: tnecniv on June 12, 2013, 12:13:29 PM
Quote from: Thecomedian on June 12, 2013, 03:26:33 AM
this may not need to be asked but.. is there a bridge wire connecting the ground side of the pot to the base of the pot, or any wire connecting the pot base to Ground?
No, the base goes directly to the output jack and ground goes to ground (theoretically, there might be a short somewhere that I have yet to discover)
I see. My ibanez uses a jumper wire from the ground lug of the volume pot to the base of the volume pot. I've always done my pots like this to keep interference out after seeing the schematic for the ibanez.
Im trying to understand if you mean the base of the entire pot goes to the output. Would that mean that any interference signal that your pot's body gains is going to the output jack?
Does it work if you place everything inside the enclosure except for the pot?
It seemed the issue was the pot, I now have a fully enclosed circuit and it sounds great. Now my only problem is coming up with a good name for it. Thanks for all the help!
Congratulations on your first pedal!!! :)
>Now my only problem is coming up with a good name for it. Thanks for all the help!
How about the "Perseverance Drive"? ;D
"drive me potty"