Help with Aion Graviton Pedal

[thursday2]

Hello, I'm working on my first pedal project, the Graviton, Aion's HM-2 clone.

Right now the issue I'm having is that when I have the pedal activated, the LED light is illuminated, and the usual feedback I get when my amp is plugged into certain outlets is "distorted."  Using a multi-meter, I get all the right readings on the ICs and transistors.

Nothing comes through (other than the aforementioned feedback) whether the pedal is activated or not.  I suspect the problem is centered around the input/output PCB.

As you may be able to tell, I don't have the vocabulary to talk about this issue.  Any help would be appreciated. 

[bluebunny]

Welcome to the forum!

1. Take some pictures of what you've done.  We like pictures.

2. Check out the sticky "Debugging..." thread at the top of this sub-forum.  Follow the instructions and post here.  It really works.

[thursday2]

Thank you so much!

Name of the project: Graviton, from Aion Electronics

Link (to PDF):  https://www.dropbox.com/s/9ltovgfs6myaxxw/graviton_kit_documentation.pdf?dl=1

Admissions:  None to speak of other than working on the enclosure first so I would be able to make sure everything was still able to fit without shorting as I was soldering. 

Substitutions or modifications: None

Ground:  Apparently negative as I ground the black end of the multi-meter when testing it.

Sounds:  Seems to distort normal hum feedback amp has when plugged into certain outlets, no guitar sound goes through when pedal is activated or otherwise

Voltages:

Q1
D = 9.16
S = 482
G = 2.29

Q2
C= 3.91
B= 0.6
E= 0

Q3
E= 8.37
B= 7.46
C= 3.79

Q4
C= 9.16
E= 3.65
B-2.95?

IC1
P1 - 3.78
P2 - 3.78
P3 - 3.78
P4 - 0
P5 - 4.25
P6 - 4.57
P7 - 4.58
P8 - 9.16

IC2
1 - 4.58
2 - 4.58
3 - 4.57
4 - 0
5 - 4.21
6 - 4.58
7 - 4.58
8 - 9.16

IC3
1 - 4.58
2 - 4.58
3 - 4.15
4 - 0
5 - 4.58
6 - 4.58
7 - 4.58
8 - 9.16

Regarding diodes...I figured out after starting this that diode 8 (1N914) was pointing in the wrong direction.  I have extracted it but will probably need to use another one i have from a previous attempt...
Hopefully in doing so I haven't irrevocably damaged this thing.  LED still goes on without diode.

[thursday2]

[DIY Bass]

Th esoldering on the tone pots at least looks a little iffy.  It looks like at least some of the connections have little blobs of solder sitting on the pot legs that do no properly wet the solder pads and connect.  reflow those joints until they look good and have a look across the board to see if any other joints are bad.  I couldn't see the gain/volume pot soldering but you should look carefully there as well

[bluebunny]

Yes, definitely reflow those pot joints.  You want to aim for a little concave cone, not a sphere.  Make sure your iron is hot enough (if you can adjust it) - the bigger pads and parts here require more heat than, say, a resistor.  Photos of the other side of the board would be good too.

[bushidov]

Yeah, I agree with the above posts. That needs reflowed on the tone pots, which suggests there may be other ones that need reflowed too.

[thursday2]

Thanks everyone, i resoldered (still not great) the pots and they all alter the signal (i.e., the hum), so thats good. The  cable reacts when i touch it and the signal changes when i touch the strings. However, my guitar still doesnt actually come through whether or not pedal is activated.  Ive attached more pictures.

Thank you again, and stay healthy!

[mcknib]

What wattage soldering iron are you using

You've got a fair amount of what look like dry solder joints and joints with too much solder which are invariably dry inside

Most of your diodes look like they have poor connections D5 and D6 in particular I'd reflow those and make sure you get nice joints there too much heat can damage them so you don't want to have your iron on them for more than 4 seconds or so

You can clip a small croc clip on the legs at the diode body as a heatsink then heat the solder making sure it flows onto the solder pad and diode leg for a good connection

Watch you don't get burnt whilst holding it in place though! it'll get hot you may have to reflow a few other joints but I'd start with D5 and 6 and see if that gets you any audio

[j_flanders]

Several of those voltages are off or at least suspicious.
Below are the reference voltages from the build doc pdf, compared to your voltages:

Voltages:

Q1
D = 9.16
S = 482
G = 2.29

Q2
C= 3.91
B= 0.6
E= 0

Q3
E= 8.37
B= 7.46
C= 3.79

Q4
C= 9.16
E= 3.65
B-2.95?

IC1
P1 - 3.78
P2 - 3.78
P3 - 3.78
P4 - 0
P5 - 4.25
P6 - 4.57
P7 - 4.58
P8 - 9.16

IC2
1 - 4.58
2 - 4.58
3 - 4.57
4 - 0
5 - 4.21
6 - 4.58
7 - 4.58
8 - 9.16

IC3
1 - 4.58
2 - 4.58
3 - 4.15
4 - 0
5 - 4.58
6 - 4.58
7 - 4.58
8 - 9.16

Especially Q1 S(ource) and Q4 B(ase).
But also some of the voltages on the op amp pins should be closer to each other and closer to mid supply voltage (9,16/2 = 4,58)
Here's the schematic:


With that, maybe someone with more knowledge than me has an idea what could cause these incorrect voltages and provide a possible solution. Or at least provide a logical way of handling the problem solving.
Most of the soldering doesn't look that great but if you just mindlessly keep reflowing solder joints you'll eventually burn out a component and then it will be even harder to solve.

Do you clean and tin the tip of your soldering iron often enough?
Here's a good read:
https://www.weller-tools.com/how-to-care-for-soldering-iron-tips/
A very important part is this:

It's essential to keep your tip tinned, since iron oxidizes rapidly. Oxidation prevents the tip from transferring heat efficiently.

A dull looking tip will not be hot enough and will not transfer heat well or fast enough to solder properly.

You should tin your tips before and after each soldering session, as well as in between soldering every two to three joints. You want to keep your tip tinned at all times, from the first time you use it until you discard it. When you tin a tip, you cover it with a thin layer of solder.

It's something I didn't know when I started soldering.

[DIY Bass]

It sounds as if you are not getting sound on bypass?  The circuit for bypass pretty much goes input jack - switch -output jack.  That should work even if there is no power to the pedal.  If you have a multimeter and know how to use it to test continuity, then use it to check the bypass pathway.  If you have one but don't really know how to use it then ask and we can help you out.  If you don't have one then look up about building an audio probe and use to trace the signal on bypass and see where it stops.

[duck_arse]

just for my own curiosity, can you please read us what is marked on the capacitors C3, C7, C8, C13?

[mcknib]

DIY Bass makes a good point if you're not getting bypass signal you may not be getting any audio in at all in bypass or effects mode

Looking at your IN jack tip connection it does look a tad dull

I know you shouldn't constantly reflow joints but in the absence of an audio probe probs the quickest thing to do, all it needs is for you to hold your iron tip on the connection for a few seconds till you get a nice flow making sure your irons not set to too high a temperature you're hopefully not using unleaded solder

I set mine around 400 degrees c

As DIY Bass says also easy enough to continuity check your input output connections to make sure they're good

You've definitely not picked the easiest first pedal to build that's for sure

If you want to build an audio probe and start using it here's a super simple probe

All you need is a mono jack, a film or ceramic capacitor from 100nf to 1uf, a croc clip and a coupla bits of wire

Solder your ground wire to the jack ground lug, croc clip to the other end, solder 1 leg of your cap to the jack tip lug, probe wire to the other leg of the cap that's it, shown below a quick dirty demo you'd want a longer wire for your probe end



Here's a wee PDF explaining the probe how to use it etc scroll past the bit on building a posh probe

https://drive.google.com/file/d/1T9OsJ0riQhm1QFWPfNQ5q5guikuFKDRN/view?usp=sharing

A quick touch to your IN pad with your probe and you'll know if audios getting in or not and take it from there

[thursday2]

Awesome, thanks. Im running to home depot to pick up a finer point and a desoldering pump (so far ive just been using wick). Ive been using a dry sponge to clean off residue, but i reckon i should pick up some steel wool. Is there anything else i might need?

My iron is a 25 watt weller.

Ill get back with those other readings but havent quite figured out how to test the input and output.

My priority right now is figuring out how to get it to play clean at least, so maybe clean those two boards up first huh?

Thank you all again.

[bluebunny]

Don't get too fine a point - you'll have trouble transferring heat efficiently enough to get the solder flowing correctly over your joints, particular on jacks and pots.  I'm using a 2.3mm tip like this for pretty much everything:



And wet your sponge.  I know it will temporarily cool the tip, but unless you're doing a joint every second, this isn't an issue.

[Slowpoke101]

Just out of interest's sake....

Have you tested the cable between the guitar and the Graviton. Also the cable between the Graviton and your amp?

I also suggest checking the guitar as well. From your fault description it really does seem that the ground connection between the guitar and the amp (plus whatever effects are between them ) is missing / broken.

[thursday2]

The cables and guitar seem to work fine with the old flanger i have. 

What is the proper setting to test the non-polarized capacitors and the bypass path with just a multi-meter?

thank you for all the tips on caring for my iron. 

[mcknib]

You can't actually check components accurately in circuit because they may be affected by adjoining components like resistors etc

First thing I'd do as someone suggested is check your grounds which is fairly easy with it in it's enclosure

You don't need to power it up to do this you're just checking for continuity to ground

Select continuity check on your meters dial looks like this with 1 or both of these symbols below if it's an auto ranging meter it's usually the ohms position and you just hit the range button until the radiating beep symbol appears on the display

To check you've got it in continuity test mode just touch the 2 probes together and it should beep



Stick one probe in a screw hole of the enclosure and touch your ground connections with the other probe if it's connected you should hear a beep if not it'll show infinite resistance either a 1 or OL will be dispayed and it won't beep meaning there's no connection to ground

We know you're getting power to the pcb so you don't really need to check the DC jack I'd check any pads labelled GND and your jack sleeve connections (S) you should be able to stick your probe into the back of the white plastic plugs to test if you have to remove them make sure they are fully inserted when you put them back, you should hear them click into place when fully inserted

[thursday2]

I get readings for all wires marked ground as well as the jack sleeve components.  I'll double check that in jack connection. 

[mcknib]

Do you mean you get 0v on your grounds or are you actually getting a voltage reading or do you mean it beeps in continuity mode I'm not sure what you mean