AION FX Quantum Build - Requesting Help

[peterfrergusonproductions]

Hello!

This is my second Aion Build. The first one I did worked (and is working) great on the first try. This second one - I'm having some issues. This is the Quantum, the MT-10 PCB. I bought the full kit, so all parts were included.

The pedal powers up, LED lights up, but it doesn't pass signal regardless of bypass state. There is no buzz, hum, or anything of that nature.

I get different readings on the IC depending on if a 1/4" cable is plugged into the input jack. Transistor readings aren't affected by this.

IC readings w/o 1/4" cable plugged into input jack:
1: 4.52
2: 4.52
3: 4.41
4: 0
5: 4.435
6: 4.518
7: 4.518
8: 9.06

IC readings WITH 1/4" cable plugged into input jack:
1: 4.42
2: 4.42
3: 4.05
4: 0
5: 0
6: 0
7: 0
8: 9.06

Q1
E: 5.24
B: 5.6
C: 9.06

Q2
E: 3.55
B: 3.98
C: 9.06

Here's the build documentation.
https://aionfx.com/app/files/docs/quantum_kit_documentation.pdf

Attached is a photo of my build. I am a working pro player, and I build these to use live and in the studio. I'm pretty good at following instructions, but not too savvy on reading a schematic. Any help would be deeply appreciated!

Peter

[eh la bas ma]

Hello, welcome !

I'd suggest to perform a simple audio-probing test, to quickly find where the signal stops.

Here is a link to build an audio probe :

http://diy-fever.com/misc/audio-probe/

Here is the signal path on your schematics, you'll have to probe the components's pads from IN to OUT :



Once you found a spot where the signal stops, you should check the components in the aera for shorts with continuity tests, check the soldering, reflow the pads, check the values, etc.

Just in case : a piece of cardboard or some thick tape should be stuck on the back of the pots, to prevent them from shorting the pcb soldering side.

Edit: I'm not sure about the different readings when the jack is inserted. I would check, with continuity tests, if the cable jack is correctly connected to the right terminals (tip/IN and ring/Ground), and if the 3PDT breakout board's IN pads are ok : PCB IN pad  should be grounded when the effect is switched off, and connected to Jack IN when switched on.
Also, make sure the jack's daughterboards aren't shorting the main pcb or the 9V DC connections.

[duck_arse]

also welcome.

28 pages! that is some manual. and yet, the circuit diagram shows no sign [that I could see .... ] of either the bypass switch or the I/O jacks. so, we can't conject as to what is happening, whether the supply on-switches with jack plug insertion or not. or whether the empty batter snap might be shorting to case. perhaps isolate those lugs if unused, retest. is the behaviour aberrant when batter powered?

does bypass affect the voltage readings? cvan you provide VA, VB and VC voltages, and do they change w/ plugging and/or bypassing?

[peterfrergusonproductions]

Thank you so much!

These kits have plastic dust covers on the pots that should prevent shorting, at least I think they would do that.

Checking continuity on the jacks. With a cable plugged in to the input, the tip of the plug is show continuity with Jack In, and shows continuity with ground pads when the effect is off.

Checking continuity on the 3PDT breakout PCB - when the effect is on, PCB In is not grounded and shows continuity with Jack In. When the effect is off, PCB In is grounded and does not show continuity with Jack In. So that is all correct, I imagine. There is no continuity between Jack In and Jack Out, or Jack in and PCB Out.

I will need to make one of these audio probes. Thank you so much for highlighting the signal path! This morning, I am noticing that if I play a guitar into the pedal, the LED clipping diodes light up. So the signal must be making it at least that far, correct?

[peterfrergusonproductions]

also welcome.

28 pages! that is some manual. and yet, the circuit diagram shows no sign [that I could see .... ] of either the bypass switch or the I/O jacks. so, we can't conject as to what is happening, whether the supply on-switches with jack plug insertion or not. or whether the empty batter snap might be shorting to case. perhaps isolate those lugs if unused, retest. is the behaviour aberrant when batter powered?

does bypass affect the voltage readings? cvan you provide VA, VB and VC voltages, and do they change w/ plugging and/or bypassing?

Pedal powers on regardless of jack plug insertion. I'm not sure what you mean by 'empty batter snap.' I will try with a battery! That's a good idea. I will check those voltage readings and report back.

[duck_arse]

I see the battery snap lying against the case, and I'm wondering if one of the lugs is making contact with the case, which should be grounded. you would not have this problem, if it is a problem, with a battery clipped in, see.

[peterfrergusonproductions]

I see the battery snap lying against the case, and I'm wondering if one of the lugs is making contact with the case, which should be grounded. you would not have this problem, if it is a problem, with a battery clipped in, see.

Ah, this is a good point. I'll check it out.

[peterfrergusonproductions]

Hello, welcome !

I'd suggest to perform a simple audio-probing test, to quickly find where the signal stops.

Here is a link to build an audio probe :

http://diy-fever.com/misc/audio-probe/

Here is the signal path on your schematics, you'll have to probe the components's pads from IN to OUT :



Once you found a spot where the signal stops, you should check the components in the aera for shorts with continuity tests, check the soldering, reflow the pads, check the values, etc.

Just in case : a piece of cardboard or some thick tape should be stuck on the back of the pots, to prevent them from shorting the pcb soldering side.

Edit: I'm not sure about the different readings when the jack is inserted. I would check, with continuity tests, if the cable jack is correctly connected to the right terminals (tip/IN and ring/Ground), and if the 3PDT breakout board's IN pads are ok : PCB IN pad  should be grounded when the effect is switched off, and connected to Jack IN when switched on.
Also, make sure the jack's daughterboards aren't shorting the main pcb or the 9V DC connections.

You were right, the jack's daughterboard was shorting to the main pcb. I put some tape in between and all is working perfectly. Thanks everyone for your insight and assistance! The DIY community is very cool.