SOLVED kind of a dream fuzz build...

[e_man_89]

O.k., my son gave me one of those chinese finkelstein fuzz pedal kits for christmas.

Upon studying the pcb, (there is no schematic provided) I find that it is basically an opamp fuzz without the tone switch.

When comparing the BOM (the kit and the Dream Fuzz) for each, it is part for part right down the line.

Anyways, when the effect is engaged, I get no sound unless I hit the strings of the guitar very hard. Then I get "spurts" of noise.

I have checked component values until I'm cross eyed. Everything is what the PCB and the Dream Fuzz call for.

I measured voltages at the IC's. They are as follows;

IC1 - JRC4558
Pin
1 - 1.44v
2 - 0.15v
3 - 3.89v
4 - 0
5 - 1.37v
6 - 1.57v
7 - 1.47v
8 - 8.55v

IC2 - UA741CP
Pin
1 - 0
2 - 4.7v
3 - 3.24v
4 - 0
5 - 0
6 - 4.7v
7 - 8.55
8 - 0

Any help is appreciated. Thanks.

 

[fig]

A picture or two would be very useful to your cause
The opamps appear to have voltages at the correct pins.

 

[BuddytheReow]

Pics or we can't help! It may not be the opamps causing the problem.

 

[e_man_89]

This is the component side. The labels on the pcb are the instructions. There is no schematic. I have verified component values 3 times.
The IC on the right is a UA741.


Please don't solder judge me. I had a heck of a time getting the pads on the board hot enough to flow solder well.

Thanks guys.

 

[e_man_89]

BTW, to reiterate, when I strike the strings of my guitar hard, I get a "spurt" of sound from the pedal. Checked things with a diy audio probe and didn't find any failed components.

I know I'm missing something, but it's got me stumped right now...

 

[BuddytheReow]

I think your right IC is upside down?

 

[e_man_89]

Thanks for taking a look Buddythereow.

If you look carefully, you can see the diagram on the pcb under the chip. The "notch" for each chip's socket was portrayed opposite of each other.

Pin one on each chip is oriented the way the pcb diagram shows it.

 

[e_man_89]

I figured this one out. One of the pads had separated from the copper on the board.

I found it using a sound source (little mp3 player, a 100nF cap, and an old meter probe). Worked from the input step by step until I got sound, and boom, there it was.

Thanks to chuck d. bones for a post of his that gave me the idea (don't remember the thread).

Thanks to all who commented.