Particle Accelerator - Treble Knob Not Working

S

Slugsmoreslugs

New member
Hey gang,

I'm new to the forum, nice to meet you all! I did some digging and didn't see anything come up related to this question so here it goes:

I just completed two particle acelerator builds as christmas presents, one turned out perfectly, one seems to be having issues.

On one of them, the treble knob seems to have no effect, everything else on the pedal is working as planned. Signal is passing through, Bass and Mid knobs are working as expected. I measured the pot with a multimeter and I'm getting 200kOhm at full sweep, so that doesn't seem to be the issue. From here, I'm not entirely sure what to look for next. I looked at the schematics to see if there are any resistors/capacitors obviously in the treble part circuit but I have fairily limited knowledge on electronics (beyond a few other pedals I've made) and was hoping someone could point me in the right direction.

Any/all advise is welcome!

Link to the documentation here: https://drive.google.com/file/d/1hTBLm8h9MuoW78s2rnoN8JPGLF7RQALe/view

Thanks!
 
Hey #Slugsmoreslugs,
Welcome to the forum!
I'd love to see your soldering around the treble pot. I'm wondering if you have created a solder bridge across some of the pot pins.
 
treble pot.jpg Here you go! I reflowed the joints before the picture was taken, I tested it again and no dice.

On further examination it seems like there just isn't any treble in the circuit. Compared to my functioning unit, when I completely dial down the bass and mid knobs, only the trebley parts of the signal come through. On this unit however, there is just no sound when removing the other frequencies.
 
How did you measure the pot? Lug 1 and 3? Does the resistance change if you measure from lug 3 to the others?

Did you measure and confirm the width ther resistors and capacitors in the tone stack?
 
Slugsmoreslugs said:
View attachment 107633Here you go! I reflowed the joints before the picture was taken, I tested it again and no dice.

On further examination it seems like there just isn't any treble in the circuit. Compared to my functioning unit, when I completely dial down the bass and mid knobs, only the trebley parts of the signal come through. On this unit however, there is just no sound when removing the other frequencies.
Click to expand...
Hello Slugsmorelugs,

You could check again the soldering on C5, when you dial down bass and middle they are connected to ground, and signal should go through C5. (and treble potentiometer)
 
Either the solder joints on C5 is bad or there is a small crack in the copper track on the PCB, for the Treble to work the signal has to flow through C5 and the treble pot.
Check the resistance from the solder joint on the capacitor to the solder on the pot, also check the resistance from the other leg of C5 to R8 and R10, if the resistance is close to 0 then I would guess that C5 is no good.
 
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