No sound with an Aion Cerulean (original PCB) Morning Glory variation

[ynicorns]

Hi all, I think this is my first post, but I was surprised to find I'd apparently registered an account sometime in the past and forgotten.  Anyways, I'm deep into my first DIY build and have yet to make the thing work.  I read the post on debugging and so I've been trying to go through part by part and determine where the issues are.  I've fixed a couple things but I've found a strange thing I can't explain - the schematic here (https://www.dropbox.com/s/h0kwg36lq1tw9g0/aion-cerulean-bb-documentation-v2.pdf?dl=1) shows R1 going out to pin 5 on the IC (I THINK!  I'm new to reading schematics) but when I'm testing the circuit for continuity between parts it seems as though R1 is connecting to pin 3 on the IC... am I reading the schematic wrong or do you have any thoughts on what's up?  All help appreciated, thanks in advance!

[ynicorns]

Trivial detail - I just realized I asked a ton of questions in 2014 about a completely non-stompbox design, everyone was super helpful then, sorry to the community for forgetting I already had an account here, haha

[Marcos - Munky]

You're correct on R1 being connected to pin 5... one of the terminais is connected to pin 5. The other one is connected to the VR line (reference voltage), and pin 3 is also connected to VR. So one terminal of the resistor have continuity to pin 5, the other one have continuity to pin 3.

Post a few photos and what is happening to your build, and we can help you to fix it. Do you know how to do a audio probe test?

[ynicorns]

Hey all, thank you for the initial response, sorry for the delay in mine, it's been a busy couple of weeks and I just got to dive back into pedal things tonight.  I ended up rewiring the switch from the last time I tested it (I had been using a mix of too heavy a gauge stranded and solid core wire and recently got in some 24awg that seems much more suited to the job) but unfortunately we're getting the exact same results.  True bypass mode works fine, but as soon as I engage the pedal all I get is a quiet noise floor that raises and lowers with the volume knob.  I've got some pictures of the build now, and if I can figure out how to upload it here a video, though it's probably not too useful as the pedal is just either bypassed or killing the signal.










Any thoughts on what to try to make this work based on my last post's more technical info?

[ynicorns]

[ynicorns]

I've seen audio probe testing a couple times on youtube but I'm not really sure the best way to get started learning how to, I'm guessing there's a good thread here somewhere that could teach me?

[MikeA]

If you don't have insulators between the pot casings and the PCB, you may have one or more shorts between the solder side of the PCB (component legs) and the back of a pot.   If you can slip a piece of thin cardboard, credit card or even paper between the pots and the PCB that should insulate it.  Or maybe you can pull the PCB up and away from the pots just a little, but that's tricky with the toggles and pots soldered in.  Worst case, remove the nuts from the toggles and pots, lift it all up and check for shorts/insulate between, then reinstall.  For his Aion PCB builds, Kevin recommends the Small Bear "Dust Cover for 16mm Pots" as insulators. 

If that's not it, tracing the audio path is next. One resource:  https://www.diystompboxes.com/pedals/debug.html    If you do trace it and get as far as the output stage, be aware there's a minor error in the schematic there, the correction is attached.  I've built this one before.  Mike

[willienillie]

True bypass mode works fine, but as soon as I engage the pedal all I get is a quiet noise floor that raises and lowers with the volume knob.

Do the other knobs have any effect on the noise?

Where did you get the IC?  Have you tried a different one?  Pretty much any dual opamp you might have handy should work, 4558 or whatever.