Fuzz circuit - no sound

[Kerosenetrewthe1]

Hello all,

This is my first diy stomp box and it's a mastodon fuzz pedal kit. The build went smooth until I plugged it in. My bass signal goes through the pedal in bypass mode, but when the pedal is engaged, I get nothing. No hum, no buzz. Complete silence. I checked for bridges in the solder and scrapped between all the joints. Here's a couple pictures. Maybe somebody can see something I'm missing? Seems to be a grounding issue?

Thanks in advance for any help and advice.

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[Cozybuilder]

Double check that your guitar is plugged into the input, and the amp to output. Power to circuit? Ground to both jacks?

[Elijah-Baley]

Yes. With the multimeter check all the wiring.
The led is turn on, right?

[Kerosenetrewthe1]

Double check that your guitar is plugged into the input, and the amp to output. Power to circuit? Ground to both jacks?

Thanks for the replies,

Yes, I'm getting power to the circuit. The led turns green when the effect is engaged, and red in bypass mode. I installed the jacks to the box to ground them and got the same result. Wondering if I have a bad switch? I didn't see a marking on the switch, do they have an orientation?

[Elijah-Baley]

You can check the lugs with the multimeter and see if the switch works fine. Do you know how switches work?
Fantastic image: http://www.diystompboxes.com/beginner/123DT.jpg.

Trace the signal through input-footswitch-output, could be a simple wiring problem. Check the wires on the board, too.

[Kerosenetrewthe1]

You can check the lugs with the multimeter and see if the switch works fine. Do you know how switches work?
Fantastic image: http://www.diystompboxes.com/beginner/123DT.jpg.

Trace the signal through input-footswitch-output, could be a simple wiring problem. Check the wires on the board, too.

Great link, thanks! The switch checks out okay. I started to trace the board and I didn't get continuity between the two points circled on the picture below. It looks like there is a wire track on the board but I'm having a tough time knowing for sure.

[Cozybuilder]

The schematic is a big help:


The junction of R8 and R3 should be 9V, R8 is the CLR, R3 is the Q1-Collector resistor. Take a voltage measurement on each side of R3. If its 0, then you need to connect R8 and R3.

[Kerosenetrewthe1]

The schematic is a big help:


The junction of R8 and R3 should be 9V, R8 is the CLR, R3 is the Q1-Collector resistor. Take a voltage measurement on each side of R3. If its 0, then you need to connect R8 and R3.

Holy crap! That was it. Man, this feels good. I've been tracing this for two days. I'll post a picture of the completed pedal in a few minutes. Thanks again for yours and everyone's help!

[Kerosenetrewthe1]

The schematic is a big help:


The junction of R8 and R3 should be 9V, R8 is the CLR, R3 is the Q1-Collector resistor. Take a voltage measurement on each side of R3. If its 0, then you need to connect R8 and R3.

Cozy,

The pedal works great but I'm getting some pop when I click on and off with the footswitch. I did some searching and found I need to add a 1M resistance pull down. According to my board, is it something I can solder in line?

[Cozybuilder]

R1 is the pulldown resistor. Verify: 1) value; 2) that it connects to C1 at one end, and the ground plane at the other.

[Kerosenetrewthe1]

R1 is the pulldown resistor. Verify: 1) value; 2) that it connects to C1 at one end, and the ground plane at the other.

Thanks for the reply. R1 is reading just over 1M so I'm assuming replacing it or adding another 1M resistor in series won't help. Or would adding more resistance to the pull down circuit help?

[Cozybuilder]

Since the resistor value is verified, then the most likely problem is either a bad connection to ground or to the input side of the cap (C1). I would try reflowing the solder on both ends of that resistor (R1).

[Kerosenetrewthe1]

Since the resistor value is verified, then the most likely problem is either a bad connection to ground or to the input side of the cap (C1). I would try reflowing the solder on both ends of that resistor (R1).

I checked all my grounds and I had a weak solder joint on the input side of my jack. Seems to be much better now. Thank you,