Is my DPDT wired completely wrong?

[Kwagmire Wagner]

I wired up what I thought would be a simple true bypass looper pedal off of Beavis Audio and what turned out to be a $14 brick. As it turns out, I'm kinda crap at this. The most likely possibility is that I have wired the DPDT toggle wrong. Are their post orders (pin outs) different from switch to switch? Here are some pics of the beavis audio plan I was following and what my looper box looks like. As you can see, I swapped the send and return arrangement but not the wiring simply so it would fit into my pedal board better:









Help me Obi-Wan Kenobi... because I am hopeless.

[peterg]

Looks like your output jack tip is touching the enclsure. Check the other jacks for unintentional grounding as well.

[Jdansti]

^+1

If that appears ok, then check your switch for continuity in each position. The switch could be bad.

[mth5044]

Looks like the input tip could also be touching the enclosure.

[Kwagmire Wagner]

I went through and adjusted all the jacks to make sure they weren't touching anything and it made no difference so I pull all the guts out of the enclosure and tried it again. Still nothing. I then set to the DPDT with my multimeter and my suspicions tell me that it is spun 180 degrees to the way it should be but I'm not sure. I can't tell which poles should be inputs and which should be outputs. I went through and could see continuity between certain contacts and see how it would change when the switch was thrown but can't figure out the exact pinout. How does one do this when there's no labeling on the contacts etc.?

[Kwagmire Wagner]

The contacts on the left side of the DPDT are always connected in both switch positions.

The lower and center right contacts are connected in and when the switch is thrown, the center and upper right contacts are connected and the lower right is not.

The right side and the left side contacts do not ever seem to be connected and this must be the reason for run the lead from the upper left to the lower right contacts.

Thus...
Switch Position one, the signal would run from the input, to the upper left contact, down the bridging lead to the lower right contact which is connect via the switch to the output providing the clean and direct signal.

Switch Position two, the signal would run from the input, to the upper left contact, to the middle left contact via the DPDT internal connections, to the send jack, through the effects and back through the return jack, back to the upper right contact and would bridge to the middle right contact via the switch and then to the output.

What the fuzz? Why does this dirty bastard not work?

[peterg]

What you have labeled input is wired as out. What is labeled output in wired as in.

[Kwagmire Wagner]

Yeah, you're correct on that one. My photoshop mistake. Still, the connections are correct and I have been plugging in to the correct input and out of the correct output.

[davent]

The contacts on the left side of the DPDT are always connected in both switch positions.

...
What the fuzz? Why does this dirty bastard not work?

If they're always connected your signal is always shorted to ground, somewhere there's a bridge and we can't see it from here.
dave

[mth5044]

It helps to think of the DPDT as two separate switches. The way you described the right side is correct and is one individual switch. The left side should operate in the same way and neither should be connected unless you put in a jumper. You can turn the switch 180 degrees and it will still operate the same exact way since a push switch doesn't show any direction in operation, unlike a toggle switch.

With each switch, the middle lug is common, or the pole (dPdt). The D in each case is for double, so you know there are two individual switches inside. The pole connects to the top and bottom lug via the internal switching mechanism and can only go one of two ways, thus the double throw. Most switches will operate as if there was a mirror down the middle, so when the left switch has the pole connected to the top lug, so does the right.

Anyway, if your left switch has both contacts connected all the time, there is either something wrong inside the switch (if you heated the lug up too long, it can cause problems), or there is something wrong with your wiring as Davent says.

Also, the amount of times I've gotten confused flipping a pedal right side up with regards to plugging the ins, outs, sends and returns in is laughable. Triple check what you are plugging into, especially because your layout is incorrectly labeled. I know you have checked it and you are rolling your eyes at the suggestion again, but do it! 

[Jdansti]

To help with troubleshooting, I've outlined the continuity paths for the two switch positions and provided a test procedure. For the purists, the arrows don't really show the way that electrons flow, they're just there to help with troubleshooting.  

POSITION 1 CHECK



1) Place one lead on the INPUT jack tip lug and the other on the OUTPUT jack tip lug. You should have continuity.

2) Place one lead on any jack's sleeve lug and the other on the SEND jack tip lug. You should have continuity.

3) Place one lead on any jack's sleeve lug and the other the INPUT and OUTPUT jacks' tip lugs. You should not have continuity.

4) If any of the Position 1 tests don't work. Leave the switch in Position 1 and follow the path of continuity shown in the above photo (Signal: Green--> Yellow--> Magenta--> Orange)
(Grounded Send: Blue)

--------------------------------------------------------------------------------------

POSITION 2 CHECK



1) Place one lead on the INPUT jack tip lug and the other on the SEND jack tip lug. You should have continuity.

2) Place one lead on the RETURN jack tip lug and the other on the OUTPUT jack tip lug. You should have continuity.

3) Place one lead on any jack's sleeve lug and the other on each of the jacks' tip lugs. You should not have continuity.

4) If any of the Position 2 tests don't work. Leave the switch in Position 2 and follow the path of continuity shown in the above photo.
(Signal: Green--> Magenta--> Yellow--> Blue--> Purple--> Orange)

-------------------------------------------------------------------------------------

Another test: If all of the above checks out, while in Position 2, place an alligator clip lead from the SEND jack tip lug to the RECEIVE jack tip lug and see if you have continuity between the INPUT and OUTPUT jack tip lugs.

[duck_arse]

I bought 20 X-wing dpdt's, just like yours shown. one failed on one side, constant short both contacts, just as you described. the bad dpdt switch is now a "good" spdt.

[upspoon12]

no solder on the hot wire in the jack labelled "output" ?

[karbomusic]

Sorry for not reading the entire thread but I can't possibly imagine how the tip for the bottom-left jack isn't shorted to ground and if it isn't it will be as soon as the plug hits the tip and moves it over which also may be true for any of the jacks depending on position when you plug it it.

Also, once you get it working you'll want to be aware and careful because as soon as one of those jacks loosen, it runs the risk of getting turned and shorting down the road.

[bloxstompboxes]

I'd say from the pictures, 3 if not all 4, are shorted to the chassis.

[Bill Mountain]

I just pulled my hair out (what little was left) trying to trouble shoot a simple mixer pedal.  After cutting out, replacing, and rewiring all sorts of components I discovered that the output jack had some sort of short in it.

[davent]

He wrote earlier that it wasn't working out of the box as well so more then just shorting through the enclosure.

[Kipper4]

It might seem simple but what about checking the single strand wires are intact with the DMM?
Those sometimes don't take a lot of bends before they fracture.

[Kwagmire Wagner]

Wow awesome input people! I love it.

Yeah, so I took everything out, insulated the box and replace the jacks in positions where if they were to touch the enclosure at all, they would be hitting insulating tape just to be sure because as one of you quite rightly point out, if those jacks loosen and turn, it will ground.

What I really think is happening is that the DPDT is knackered. I'm pretty sure I overheated one of the lugs as I soddered it, reheated it and pull the leads off when I realized it was incorrect and then did it again rather quickly.

Considering when it isn't connected to anything at all, the there is continuity between all three lugs on the left hand side, it means that side is now a single pole. I'll pick up a new one, cleanly install it and report back.

Thanks again for the great advice to one and all. One little project and I am learning a bunch.

[Kwagmire Wagner]

Confirmed: Bad DPDT switch. Thanks again everyone for your help.