Aion Andromeda Kit - No sound - Mystery solved

[vhollund]

Hello there.

I assembled this project yesterday
all the soldering went fine, till i discovered i had reversed the white and cables and had to de- and re- solder that without having a desolder-thingy. when resoldering i accidently switched ground and j out on the 4 leads connnector cable but I managed (with some hassle) to get it corrected though and checked connectivity with a meter, true bypass is working
but no sound when on. led works, there is voltage on both of the respective v+ dots on the ON/OFF switch board. 
Other than that I've been extremely carefull with soldering and values.

I'm suspecting the cable connectors might not be properly pushed down as there is a slight gap (normal?) but I do have true bypass and I cant seem to force it down further
I checked that the jack center is not shorting to ground
The PDF from Aion says to check IC values but without without specifying them, but here are the values i mesured:

IC1 (upper)

1 4.42
2 4.43
3 4.36
4 0
5 4.41
6 4.43
7 4.43
8 8.88

IC2

1 4.43
2 4.43
3 4.12
4 0
5 4.43
6 4.43
7 4.43
8 8.88


Photos of my built/pcb :
https://photos.app.goo.gl/qMn8LDZsxoZNpTkZ6

https://aionfx.com/project/andromeda-legacy/
https://aionfx.com/project/andromeda-natural-overdrive/
https://aionfx.com/app/files/docs/andromeda_kit_documentation.pdf

[Marcos - Munky]

Your voltages seems to be ok. Do you know how to do an audio probe test? There are sittuations where just the voltages won't help, and this seems to be one of those situations.

[vhollund]

Hello Marcos

I don't know how to do an audio probe but I will try

[vhollund]

https://aronnelson.com/diywiki/index.php?title=Debugging

I made the cable with the yellow drop cap
I  admit I have no idea how  to get from on end of the circuit to the other.


RESULTS
I checked the potentiometers contact points, and the good news is that I have full sound at the volume pot
The drive pot works too when probed and it sounds great
I get less signal probing the bass pot but maybe it is just showing what it adds to the signal (?)

The pcb output of the on/off /switch board is extremely faint as expected as it is the end of the circuit

R 26 + R 27 silent on both ends

D7 silent on the right side
D4 silent on the left side

Both saturated sound at the other end though

Where is a good place to probe/backtrack to find out where the signal is lost ?

[iainpunk]

i'd like to know if there is volume on both sides of C21, that's the last signal passing poing before going offboard, i suspect it be a bad cable or bad connection, the beeper test doesnt say how good a connection is, just that there is one. it might be intermittent as well.

cheers, Iain

[vhollund]

Hello Iain

ive checked the solder point on the pcb end of the output cable and there's no signal
but still you are probably right. possibly be a bad connection somewhere between vol pot and out.

C21 has no signal at both sides 
R26 is completely silent on both sides
R25 has full sound at hot end (getting closer)
IC1 has full sound at pin 7 (output)

No mesurable connection between IC1 pin7 and C21

It might have been a faulty circuit board to begin with(?)

Maybe soldering a cable between the to is the only solution ?

thanks

i'd like to know if there is volume on both sides of C21, that's the last signal passing poing before going offboard, i suspect it be a bad cable or bad connection, the beeper test doesnt say how good a connection is, just that there is one. it might be intermittent as well.

cheers, Iain

[vhollund]

Yes I soldered a cable beween IC1 pin 7 and the upper C21 solder joint
My knowledge is too limited to read into the schematics, and know if it alters the intended circuit path bypassing something(?), but it seems to be working. 

Thank you for the invaluable input Iain and Marco
This is my first built and probing

[vhollund]

Or so i thought
The signal disappears when I plug into the output jack
EDIT :

KONKLUSION
Here's what happened
The jack circuit was rubbing against the main pcb severing the connection between IC1 and C21
When I fixed it by connecting the 2 points with a cable it worked till I reinstalling in the casing, where the jack pcb created connectiion to the severed circuit line.
I solved it by inserting a small piece of isolation tape between the two.

Happy ever after - THE END :-D

[iainpunk]

thats a fix, but i'd still look in to moving the board around a bit to make it not touch the jack.
i'm glad that i have been usefull.

did you mean KLONclusion on conclusion? jk

cheers, Iain

[vhollund]

Haha
No that's just my Danish spelling
Am i bypassing something with the cable connection ?
I think it'll be ok. The iso tape is kind of rubbery and gloss, and it's only at the extreme where that circuit line was concerned that it touches

Now the question is if Andromeda is as good as my stock Odr-1

Probably a question of dialing and getting used to it

[vhollund]

...

[Marcos - Munky]

Nice to know you got it working. Now, time for your 2nd build

[vhollund]

Nice to know you got it working. Now, time for your 2nd build

Thank for the encouragement
I think i won't hesitate if i need to
A slight melt down due to my mistakes but it was solved.
Now I'm thinking about modding the built
I find the saturation adds alot of harshness /upper mids compared to the stock version. Making it less natural /transperant
It's a great and clearer clean/dirty and  boost though
Might there be a difference in components or built that i can remedy, to improve the character of the saturation ?

[vhollund]

When looking at the schematics aren't IC1s pin 6 and 7 supposed to be directly connected?
Because i can mesure non

I'm starting to think the harshness might be because i cut out the connection by inserting a cable from pin 7 directly to C21

Can i directly connect pin 6 and 7 with solder
Would that be correct?

Schem:

https://photos.app.goo.gl/ox3f4aZj2xkJb4ro9

[antonis]

Yes but you better do it via a short jumper (piece of solid core wire)..

P.S.
IC1B serves as an output buffer (unity voltage gain..)
In case of pin 6 & 7 disconnection, op-amp should be hitting supply rails (actually, a couple of volts lower) and output should be heavily distorted..
(can't say if that's you mean by "harshness"..)

[vhollund]

Hello
Yes great, i used a resistor leg
Thanks for confirming because i pretty much don't know the consequences, it is great help.
It seems to have solved the problem with the harshness, which then must have been the added unintended distortion.
The drive compresses nicely now
I'm glad this was due to my errors and not the built
It's still a little more mid present than the stock version but that can actually be an advantage, as long as it is not harshness.
Very cool

Yes but you better do it via a short jumper (piece of solid core wire)..

P.S.
IC1B serves as an output buffer (unity voltage gain..)
In case of pin 6 & 7 disconnection, op-amp should be hitting supply rails (actually, a couple of volts lower) and output should be heavily distorted..
(can't say if that's you mean by "harshness"..)