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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music6000

Well-known member
All the Pads in Yellow Circles should be around 8.8 volts, they are all connected!, If not ,there is damaged Trace.
Do you get 8.8v to the + side of C9 - 100uf???
In the Super Enlarged Picture you can see the trace between C9 + & VOICE Leg1, Check for Continuity!
There is also a trace from Leg1 to Leg 2, Check for Continuity again!
You will not get any power to Leg 3 until the Pot is installed, it works as a Variable Resistor to supply more or less voltage to the Yellow LED.

View attachment 21464View attachment 21466
Test with DMM set to DC volts with Black probe on GND pad & Red probe on Yellow circles!!!
 
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Jdilly

Member
All the Pads in Yellow Circles should be around 8.8 volts, they are all connected!, If not ,there is damaged Trace.
Do you get 8.8v to the + side of C9 - 100uf???
In the Super Enlarged Picture you can see the trace between C9 + & VOICE Leg1, Check for Continuity!
There is also a trace from Leg1 to Leg 2, Check for Continuity again!
You will not get any power to Leg 3 until the Pot is installed, it works as a Variable Resistor to supply more or less voltage to the Yellow LED.

View attachment 21464View attachment 21466
All the continuity checks worked. Many of the yellow pads are getting ~9v, but I highlighted the ones that aren’t (C9 100u +, and the 2 legs of B10k)
 

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music6000

Well-known member
All the continuity checks worked. Many of the yellow pads are getting ~9v, but I highlighted the ones that aren’t (C9 100u +, and the 2 legs of B10k)
From the back of the board get a piece of insulated hookup wire like you used on your Input/ Output Jacks.
Solder Wire to 1N5817 Yellow circle Pad & other End to C9 + Yellow Circle Pad.
You should have around 8.8v to C9 & hopefully VOICE Legs 1 & 2 & all the other Yellow Circles!!!
 

Jdilly

Member
From the back of the board get a piece of insulated hookup wire like you used on your Input/ Output Jacks.
Solder Wire to 1N5817 Yellow circle Pad & other End to C9 + Yellow Circle Pad.
You should have around 8.8v to C9 & hopefully VOICE Legs 1 & 2 & all the other Yellow Circles!!!
Making progress. The jumper wire got me 9V to the yellow circles. Strobe LED is still not turning on though. :(
 

music6000

Well-known member
Making progress. The jumper wire got me 9V to the yellow circles. Strobe LED is still not turning on though. :(
Have you replaced the VOICE pot, it needs that to power Strobe LED?
If Yes, then put a temporary jumper from VOICE Leg 3 to Strobe Anode pad to see if that Trace is damaged or LED is damaged!
 

Jdilly

Member
Have you replaced the VOICE pot, it needs that to power Strobe LED?
If Yes, then put a temporary jumper from VOICE Leg 3 to Strobe Anode pad to see if that Trace is damaged or LED is damaged!
So, I just added that jumper but still no light, although I’m getting 9v to both the 3rd leg and strobe Anode. What’s strange though is that I already swapped that LED earlier this week, so that shouldn’t be damaged. Any ideas?
 

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music6000

Well-known member
So, I just added that jumper but still no light, although I’m getting 9v to both the 3rd leg and strobe Anode. What’s strange though is that I already swapped that LED earlier this week, so that shouldn’t be damaged. Any ideas?
Do you have continuity from Cathode Strobe LED pad to 47k & Q2 green circles
If Yes, then your LED is Damaged:

abyss-continuity-test-q2-jpg.21263
 

music6000

Well-known member
Just checked and there is no continuity from the Cathode strobe to that 47k resistor or the other green circle.
Well, you know what is next!
Unplug Power from pedal!
Solder a Insulated jumper from the Strobe Cathode pad to the 47k pad & see if the LED lights up when you plug Power back in!
Keep the wire ends short when soldering so if the Back of the pot squashes the jumpers they don't touch other pads!!!
You can use some super glue to hold the insulated jumper ends down on the PCB if need be so they don't foul on other pads!!!
 

Jdilly

Member
Yeah. So pumped. And extremely grateful for all the help and support. Literally couldn’t have done it without everyone’s help. Especially @music6000

Hopefully Last question. Any reason why the strobe light would be on in both bypass and active mode? Could it have anything to do with the effect being weird to my test box?
 

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