Abyss build power issues

Jdilly

Member
Hi All. I'm building my second Abyss pedal build and am running into some issues, which I can't seem to resolve.

Here's where I'm at:
- I'm getting signal in bypass, but no sound when switch is engaged
- Front LED light works when pedal is engaged
- I swapped the switch and rewired that, thinking that was the issue, but it didn't help
- I had plugged in a 12V power adapter at one point by mistake when testing
- I'm new to voltage testing and reading schematics, but started tracing from the + and noticed the diode (D1) wasn't getting and voltage. I swapped that diode out and now I'm getting 9.28v from both sides, but no power beyond that (C9, IC1, IC2, etc)
- I swapped out the ICs (in case they got toasted), but still no power reading from any IC points
- Lastly, someone suggested cleaning the PCB with isopropyl alcohol, which left some residue around the connectors

Is it possible that I bricked the PCB by plugging in that 12V power? Any thoughts on what else to do?

Here's the link to the schematic: https://docs.pedalpcb.com/project/Abyss.pdf

Thanks!
 

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PJS

Active member
It is suspicious to me that you get the sae voltage on both sides of D1. You should be getting .45V drop across that diode. If not then you have a shorted diode or a short on the PCB - most likely a solder short would be my guess.
 

music6000

Well-known member
Hi All. I'm building my second Abyss pedal build and am running into some issues, which I can't seem to resolve.

Here's where I'm at:
- I'm getting signal in bypass, but no sound when switch is engaged
- Front LED light works when pedal is engaged
- I swapped the switch and rewired that, thinking that was the issue, but it didn't help
- I had plugged in a 12V power adapter at one point by mistake when testing
- I'm new to voltage testing and reading schematics, but started tracing from the + and noticed the diode (D1) wasn't getting and voltage. I swapped that diode out and now I'm getting 9.28v from both sides, but no power beyond that (C9, IC1, IC2, etc)
- I swapped out the ICs (in case they got toasted), but still no power reading from any IC points
- Lastly, someone suggested cleaning the PCB with isopropyl alcohol, which left some residue around the connectors

Is it possible that I bricked the PCB by plugging in that 12V power? Any thoughts on what else to do?

Here's the link to the schematic: https://docs.pedalpcb.com/project/Abyss.pdf

Thanks!
carlinb17 is correct with the Breakout Board, Unless you have reverse wired your IN, GND, SW & OUT on the Abyss PCB which is not the way to go!

Can you Test for Continuity on the matching coloured circles below :
Abyss ContinuityTest.jpg
 
Last edited:
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Dirty_Boogie

Active member
Hi All. I'm building my second Abyss pedal build and am running into some issues, which I can't seem to resolve.

Here's where I'm at:
- I'm getting signal in bypass, but no sound when switch is engaged
- Front LED light works when pedal is engaged
- I swapped the switch and rewired that, thinking that was the issue, but it didn't help
- I had plugged in a 12V power adapter at one point by mistake when testing
- I'm new to voltage testing and reading schematics, but started tracing from the + and noticed the diode (D1) wasn't getting and voltage. I swapped that diode out and now I'm getting 9.28v from both sides, but no power beyond that (C9, IC1, IC2, etc)
- I swapped out the ICs (in case they got toasted), but still no power reading from any IC points
- Lastly, someone suggested cleaning the PCB with isopropyl alcohol, which left some residue around the connectors

Is it possible that I bricked the PCB by plugging in that 12V power? Any thoughts on what else to do?

Here's the link to the schematic: https://docs.pedalpcb.com/project/Abyss.pdf

Thanks!
Any updates for us? We love a solved issue!
 

Jdilly

Member
Thanks so much for following up and checking in. I really appreciate everyone's fast reply and feedback. I plan on tackling this tonight (I ran out of solder - rookie mistake). I'm also planning on creating a test box with inputs, power, and switch for this and future builds. I'll reply back as soon as I'm back up and running.
 

Jdilly

Member
carlinb17 is correct with the Breakout Board, Unless you have reverse wired your IN, GND, SW & OUT on the Abyss PCB which is not the way to go!

Can you Test for Continuity on the matching coloured circles below :
View attachment 20748
Sorry for the delay. Got distracted building a test box to help with troubleshooting. :)

The red circles beep for me when I connect them together, but I’m not getting any sound when connecting any of the green spots.
 
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Jdilly

Member
@music6000 @Dirty_Boogie Along with the continuity update in the reply above, here’s where I’m getting voltage and not seeing voltage in the schematic. I also resoldered the whole board, which didn’t seem to help any (Unless I created new problems).

Ultimately I’m wondering if I fried the board after plugging a 12v adapter in here.
 

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giovanni

Well-known member
I doubt you could have damaged the board with the 12V adapter. No continuity between the green dots may mean that the diode is not soldered properly and thus you are getting no power. Looking at the solder side, I can’t really tell what’s going on but it looks like not enough solder on the diode?
 
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music6000

Well-known member
@music6000 @Dirty_Boogie Along with the continuity update in the reply above, here’s where I’m getting voltage and not seeing voltage in the schematic. I also resoldered the whole board, which didn’t seem to help any (Unless I created new problems).

Ultimately I’m wondering if I fried the board after plugging a 12v adapter in here.
It appears you may have a damaged trace between 4K7 Red Pad & 1N5817 Red Pad???
Check for Continuity on this updated Picture :
Abyss ContinuityTest.jpg
 
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Jdilly

Member
Thanks @music6000 . I think you’re on to something. Based on the new circled spots above, that’s the only spot that’s not getting continuity. I tried resoldering that area a few times and even swapped that diode out. When I go to apply the solder now, the solder doesn’t seem to want to adhere to the trace/PCB board.

Is there anything that can be done to remedy the problem?
 

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Jdilly

Member
Here’s some closeups of the area.
 

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Dirty_Boogie

Active member
How about just jumpering the 1N5817 diode, and taking power directly from the + pad? The diode is not integral to the circuit - it’s just for reverse polarity protection.

And I agree, plugging in a 12V power supply probably had no impact.
 

Jdilly

Member
@Dirty_Boogie @music6000 I jumped from R27 to the diode (D1) and am seeing more activity. I’m finally getting an audio signal in both bypass and active mode, but the strobe light isn’t coming on and am not hearing the effect. I started audio probing this AM to try to find the problem area.

Is that the right next step? I’m kinda unclear when to do continuity checks vs voltage checks vs audio probing.

Thanks a ton for the ongoing help with this. It’s beyond appreciated.
 

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fig

Village Idiot
It's a downer that you are having this issue, but know that it's providing a great learning experience for lots of people (me included). Music6000 can certainly get you there!
 

Jdilly

Member
It's a downer that you are having this issue, but know that it's providing a great learning experience for lots of people (me included). Music6000 can certainly get you there!
Thanks. Yeah. I’ve built 5 other pedals. 2 worked out of the gate, and the other 3 had some troubleshooting, but this one takes the cake. LOL.

Trying to use this one to really get a deeper understanding about testing/troubleshooting, schematics, etc. I’ve learned a ton.

And the community has been so invaluable.
 

giovanni

Well-known member
Now that we have power and signal going through, the next steps is to figure out why the lfo is not working. That involves a relatively complicated network connected to Q1 and Q2 so maybe we can start by measuring voltages at the 3 pins of each transistor just to have an idea of what’s going on there.
 

Jdilly

Member
@giovanni Heres what I’m seeing. On the readings with ~, the numbers were going up and down. I also included a screenshot with the current results of my audio probing (x = no audio)
 

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