1st pedal build: Bypass + power = no signal; Bypass + no power = signal

[oborgi]

Hi,

New member and new pedal builder here. I've been working on my first build: a BYOC micro Yellow OD kit. (I've done a few simple mods before). I have the pedal working but have a weird hiccup. When I have the pedal plugged into power, I get no bypass signal. However, if I unplug the power, I get a bypass signal. The pedal works when turned on as well. It's a 3pdt switch.

Considering that there is signal when bypassed without power, I figure it is not the input/output jacks. I'm think that something is grounding when it shouldn't. I've checked solder joints and they don't seem loose. Could this be related to the 3pdt switch? My impression is that if the bypass signal is going through in some way (unpowered), then it wouldn't be the switch -- but I could be wrong. 

[GibsonGM]

Hi Oborgi, welcome to the forum!

I'd suggest you re-check your switch wiring.  Yeah, it's probably grounding the signal somehow.    Maybe post a pic of the switch wiring if you can't figure it out (label input/output wires etc)...

[EBK]

Welcome! We all love a "first build" thread here (at least I do!).   

Could you post some pics of what you've built, and possibly a link to a schematic?
Also, you've looked through the "Debugging Page" linked above, right? 

[ElectricDruid]

Hi Oborgi, welcome to the forum!

I'd suggest you re-check your switch wiring.  Yeah, it's probably grounding the signal somehow.    Maybe post a pic of the switch wiring if you can't figure it out (label input/output wires etc)...

+1 agree, it's very likely to be the 3PDT wiring. And +1 agree about "Welcome" too!

[oborgi]

Hi everyone,

Thanks for the welcome and advice. It is good to know that it could be the switch. I wasn't sure if that could be the issue since I was getting bypass without power. I'll take a look at the pedal again later and see if I get anywhere. It has one of those pcb's with slots that fit over the lugs of the 3pdt.

The instructions are here (schematic is on pg. 22):
http://byocelectronics.com/lilyellowodinstructions.pdf

Which lugs on the switch would be the most likely to be the issue? Since the pedal works when switched on, I assume it's one of the lugs related to the pedal in the off positon. Based on my understanding, I think that is the bottom row of the 3pdt. Does that seem accurate or could it be a lug in one of the top two rows?

[GibsonGM]

....or maybe a cold solder joint?   Can you post a pic of your switch, maybe write "to input jack    to output jack' where appropriate, etc?

[J0K3RX]

Given that the switch is board mounted you have a 50/50 chance of sticking it in sideways. If you soldered it in with the correct orientation which I am assuming you did then the next thing I would check would be the continuity of the switch. Get your meter and set it to the beep/ohm setting and make sure the switch is making contact when you toggle it in all 3 positions. There is no "off" per say, think of it as 3 rocker switches in a row triggered by one switch. When switched one way each of the top lugs should make contact with each of the corresponding center lugs. Switch it again and the bottom row of lugs make contact to the center lugs and the top row are now open... These switches are susceptible to heat damage so if you happen to keep your iron on it for a little too long you can damage the switch. Dwell time with the iron should be as short as possible... You should get signal in bypass mode with no power because it's just a mechanical straight through connection from input to output. The next thing to check would be the jacks .. Input, output and power and make sure you didn't get one wired wrong. After that check the orientation of all of the components with polarity. If I had a dime for every time somebody (self included) put an IC in backwards I could probably retire by now....

You can check for a short to ground by switching the effect to the on position with a guitar cord plugged in then use your meter, black lead on common ground and then use your other lead to probe around the signal path to see if it's dead shorting to ground... Start at the tip of the input jack, if it's got a dead short to ground in the on position then I think... You can figure it out.

[oborgi]

Thanks for the additional advice. Since this is my first build, I didn't have a multimeter. I've ordered one and it should be here this week. That should help test some of the connections.

After messing around with the board, I discovered that the LED doesn't work. It did work initially but was sometimes fussy. I pulled it out and tested it on a watch battery and it didn't light at all. Not sure if that was one of the issues with the powered bypass signal or just a random other problem. I have a LED hanging around that I'm going to put in there when I get a chance.

Based on J0K3RX's comments, I also took a look at the way the board is situated on the switch. The pcb is not totally flush with the switch but it does look like all of the 3pdt pins are through the pcb holes. Still, I suppose that could be an issue. For now, I'm going to wait until the multimeter arrives before doing anything major.

[oborgi]

So I wanted to get back to give an update on this. Right now the pedal still works properly when powered on. LED works again. I now get a bypass signal when the power cable is attached and the effect is off, but it is much lower volume than the bypass signal when I pull out the power cable. Basically, I have to have the guitar volume to 10 get get anything when the power cable is attached in bypass mode.

I got the multimeter I ordered and set out on testing connections. There seems to be continuity between the each set of 3pdt top and middle lugs in the on position and the middle and bottom rows in the off position. I got continuity results checking the shields on the input/output jacks as well as the tips of the input/output jacks. I am getting the right voltage where the power jack connects to the pcb. I've gone over all of my soldering connections and reflowed any that looked questionable. I've tested the pedal in and out of the enclosure. I've spent a lot of time going over it (I got kind of obsessed trying to fix it) and I've basically run out of things that I can think to check.

At this point, the effect itself works and I have a spare loop/switcher pedal, so I think I'm just going to leave the byoc pedal always on when I have my board powered and bring it in and out of the signal chain with the loop pedal. This would work well enough for my set-up. My concern is that if I keep taking the byoc pedal apart and hitting the pcb and components with the soldering iron, I might wreck it altogether. Maybe down the line when I know more about builds and circuits, I'll come back to it and can figure out what's causing the volume drop when bypassed with power.

Thanks to everyone for the advice. I learned a lot going through this and I'm sure the multimeter will be useful on other projects. While my first build wasn't a total slam dunk, I still got a pedal that is usable and (mostly) works!

[Kipper4]

This might be a good time to link to or insert some pictures.
Someone might just see something.