SOLVED Tyrian only has sound in bypass

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onemhz

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I've been reading troubleshooting guides and continuity testing for hours now. This is only my second ever pedal build and I still have a lot to learn about how the circuits work, how to debug and such - to be honest, many of the debugging guides go just a bit over my head. The problem I have is that I only get sound in bypass. No audio comes out or LED comes on when plugged into power, input/output connected and switched to active.

I've checked continuity on all combinations of lugs for the foot switch to make sure I didn't burn out the internals or accidentally connect two that shouldn't be. I've probed all of the components that connect to ground. I've traced DC voltages all over the circuit - from the lugs on the DC jack to everything that looks like it's connected to the power circuit or VREF in the diagram. And I've even probed for AC voltage and I can at least see some response around the circuit and all the way to the output jack lugs when I strum a guitar with it all on and active - though I haven't seen a troubleshooting guide so I don't know if that's just chasing a red herring.

I've got a pair of Switchcraft 112AX stereo jacks but only the tip and sleeve are wired - tips are left side, sleeve is right, ring is center in the picture. I alligator clipped in some basic metal TRS jacks just in case I bought some crazy Switchcraft configuration that is wrong for this kind of build - but got the same result - sounds comes through fine in bypass but nothing in active. I think I wired the 3PDT like the diagram. I've got dust covers on all of the potentiometers. I've checked and re-checked that I put the LEDs in the right way around (longer lead/positive end on the "A" side and shorter/negative on the "K"). I did put a 5mm blue LED instead of red for the active circuit indicator, but otherwise I think I got everything right per the build guide. Also, forgive the extra hole - drilled for the DC jack, but realized too late that there was a bit of a space issue with the pot there.

I can't tell if I'm probing the wrong things or checking the polarity wrong. But I'd really love some ideas of what else I could've done wrong with the build or my diagnostics. Again, please treat me like an absolute beginner. Let's just say my first build didn't so much... work either.

PS: I'm dying to get my hands on the Auditorium Test Platform board. I feel like it could really help figure things out.

2021-02-22_00-38-39_155.jpg
 
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You definitely didn't accidentally plug your in to your out? it being wrong way up you'd still get bypass if you did that

What voltage do you get on the pcb power + and - pads
 
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I tried both ways just to be sure! But, no I plugged my cables in the right way.

I get 9.4v DC. I'm using a variable power adapter. It's a bit fishy itself as I have to set it to the 12v setting to get 9.4v, but I set it by what my DMM says.
 
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music6000 said:
If you push those tangs down, you can slide the Tab out so it will become a mono jack.
Confirm you are getting +9.4v on your Positive + terminal on PCB

View attachment 9906
Click to expand...
I thought so too. The jacks actually seem to work backward - the ring and tip are connected when unplugged and open when a cable is plugged in. I was trying to put a battery on my other board and it seemed to get power until the cable was in... oddly, their support rep said you can’t change the configuration.

I had to go re-probe a couple more times. The display on my DMM isn’t the clearest but I think I might be getting -9.4v with the red probe on the + terminal and black on -. So maybe my issue is the polarity of the power adapter? I’m pretty sure I soldered the black wires to the negative lug on the jack and used them for negative terminals on the PCB. The adapter reads -9.4v with the black probe on the outside and red stuck inside.
 
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UPDATED: Try this, Disconnect Power supply from pedal, Get your 9v Battery & make sure you put the negative lead on the Input Jack Negative Tab
Put the Positive Battery lead on + terminal on PCB & see if it fires up.

Your Switchcraft jacks are called 112A Enclosed Mono Jack, Shunt Tip, The tip is switched when no jack is inserted!
No good for Battery connection in Pedals!!!
They will still work how you have it wired.

1/4" Jack - Switchcraft, Enclosed, Mono, Shunt Tip | Amplified Parts

The Switchcraft Type 112A enclosed ¼” jack is a high quality jack featuring a switched tip. This jack has three solder lugs. One for the tip, one for the sleeve, and one for the switch which connects to the tip when no plug is inserted. These jacks have been widely used across the industry and...
www.amplifiedparts.com www.amplifiedparts.com
 
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music6000 said:
Try this, Disconnect Power supply from pedal, Get your 9v Battery & make sure you put the negative lead on the Input Jack Ring Tab you don't have connected at the moment.
Put the Positive Battery lead on + terminal on PCB & see if it fires up.
Click to expand...
I like the simple test. Thanks! It might have to wait till the morning since it’s halfway to 3am and all.
 
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The power supply is center positive - seems like the jack (https://www.taydaelectronics.com/dc-power-jack-2-1mm-enclosed-frame-with-switch.html) expects center negative - At least that's how I think I'm reading the data sheet and the voltage when plugged in (embarrassing rookie move that I didn't register the negative sign, but I'm going to continue to blame that it's right under the DC symbol so it was easy to miss...).

Trying the battery trick, but it's not working so far. I've tried connecting as music6000 described and tried connecting to the negative lug of the DC jack and a couple other spots (trying both polarities, basically) but I didn't have enough time to be thorough yet.

Thanks for the link - I had meant to buy stereo jacks I *could* use for external + battery setups but I'm still discovering suppliers and this was what seemed closest to what I'd wanted. Suggestions to find the right 112 stereo for that would be great - I like the enclosed design better than the open frame.
 
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99% of effects are centre negative

If you're not using a battery, you could wire your positive to the DC jack ground lug and your ground to the DC jack power lug then as normal to the pcb, power wire to + pad, ground to - pad thereby matching your adaptor centre positive polarity

As long as you remember to wire it from the DC jack to pcb as you normally would
power wire to + ground wire to - I can't stress that enough!

Your DC jack is the plastic type and the ground lug isn't actually connected to ground just the centre pin your middle and top power lugs are connected to each other but automatically break or switch the connection when you insert an adaptor it'll use the adaptor, and when you take it out it'll use the battery if you had one connected so leave the middle lug empty

For quick testing only I wouldn't advise keeping it like that

Battery might not work if D1 the polarity protection diode is damaged it shouldn't be but worth checking and of course if the battery is flat
 
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I tested to make sure I’m using a good battery. There does seem to be a voltage going across D1 but is there anything special to test for besides that?
I think I need to order a center negative power supply as I don’t want to have to worry about wiring all of my pedals backward.
 
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That’s a super helpful picture! I clipped a 9v battery in to the extra positive lug in the DC jack and the sleeve of the input jack to test and, miracle of miracles, it started working! I must’ve done something wrong in my hasty attempts this morning. As for the diagnosis, I have an 9v that, unloaded, reads 9.4v. Once clipped in that drops to 8.7v from the battery terminals. I can see 8.3-8.4v testing from the clipped lead on the DC jack to the ground points you circled. I also see 8.3-8.4v from the positive terminals on the ICs you circled. Does that seem expected voltage drop going through the circuit?

It seems to drain the battery quickly too - after a minute or two of being clipped in, the battery is down to 9v when unclipped. It comes back up to 9.4 a minute or two later, so maybe just the battery responding to the load?

Either way, thanks for all the help music6000 and Mcknib! I think I’m a center-negative power supply away from a fully working pedal!
 
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onemhz said:
That’s a super helpful picture! I clipped a 9v battery in to the extra positive lug in the DC jack and the sleeve of the input jack to test and, miracle of miracles, it started working! I must’ve done something wrong in my hasty attempts this morning. As for the diagnosis, I have an 9v that, unloaded, reads 9.4v. Once clipped in that drops to 8.7v from the battery terminals. I can see 8.3-8.4v testing from the clipped lead on the DC jack to the ground points you circled. I also see 8.3-8.4v from the positive terminals on the ICs you circled. Does that seem expected voltage drop going through the circuit?

It seems to drain the battery quickly too - after a minute or two of being clipped in, the battery is down to 9v when unclipped. It comes back up to 9.4 a minute or two later, so maybe just the battery responding to the load?

Either way, thanks for all the help music6000 and Mcknib! I think I’m a center-negative power supply away from a fully working pedal!
Click to expand...
Awesome!, I would invest in a Regulated 5.5mm x 2.1mm Centre - negative Power supply, not a switch mode type !
 
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Wiring your DC jack like that was just a temporary measure to test that was your only problem

I'd say you were pretty quick realising you had inverted polarity leading you to your problem it took me way longer when I started

@music6000 pics are always excellent from the many I've seen his pictures definitely speak louder!

Good to hear you'll be rocking when you get your power supply
 
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Interesting epilogue to the story: I got my fancy new multi-tap power supply and plugged it in and ... got no sound out of bypass and very little with everything cranked up on the pedal. But it wasn’t the pedal. I was just messing around with my guitar today. So the “output” cable from my previous testing was now running from the guitar to the input of the pedal (yes, I made sure I was in the input!!!) and the “input” cable was running from the pedal to my amp. Well, I pondered for a few minutes, hooked the battery back up, pondered some more and then switched them back to their original jobs and... the pedal - bypass AND active worked!

Can someone please explain why putting the cables work one way but not the other? Might also explain why the bridge pickup of my other guitar seems to depend on the cable I’m connected to... Do I just have a dozen bad cables or what?
 
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