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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giovanni

Well-known member
IIRC, on Q1 you should have 0V at the emitter, ~0.6V at the base and probably around 5V at the collector (not sure about that last one).

On Q2, the emitter should be slightly above 0V and the base ~0.6V above that number. The collector voltage depends on the voice control and should go all the way up to ~8V on one end of the pot run.
 
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Jdilly

Member
@giovanni Just double checked the transistors and I’m getting 0, .6, and almost 4 for Q1 and 0, -2.5, -2.3 for Q2

Although the values aren’t static on my meter when I touch the contact points.
 

Jdilly

Member
@giovanni For the strobe LED I’m getting .6 on the outside lead and 0 on the inner one.

Attached are also the voltage readings from the ICs
 

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music6000

Well-known member
@giovanni For the strobe LED I’m getting .6 on the outside lead and 0 on the inner one.

Attached are also the voltage readings from the ICs
We need to know about the Breakout Footswitch board to the Abyss PCB.
We know from earlier pictures that it's Upside Down.
Confirm IN to IN, GND to GND, SW to SW & OUT to OUT.

You need to Clean the Board on the solder side, it's nasty!


screen-shot-2022-01-02-at-10-13-13-pm-png.20735
 

Jdilly

Member
We need to know about the Breakout Footswitch board to the Abyss PCB.
We know from earlier pictures that it's Upside Down.
Confirm IN to IN, GND to GND, SW to SW & OUT to OUT.

You need to Clean the Board on the solder side, it's nasty!


screen-shot-2022-01-02-at-10-13-13-pm-png.20735
This is an earlier photo. Since then, I removed this switch and made a test box (see attached). To see if the test box was working properly I did a continuity check with the in and out probes in both bypass and engaged mode.

Since then I’ve also cleaned the board with 90% alcohol and a toothbrush, although, I think it can still use some more cleaning. I think I may have been too gentle the first go around. It still looks “dirty”

Here’s the latest
 

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Jdilly

Member
I’m not sure if this is what you mean, but I have the black probe from the multimeter attached to the ground wire on the bottom of my effects PCB and probed the two points where the strobe LED are with the red multimeter probe to get the .6v and 0 reading.

I had the effect engaged and something plugged into the input and output when taking the reading also.
 
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