Fuzz Factory burning problem

[heyveno]

I have a problem with my first fuzz factory. I used the layout available on effectslayout.

I didn't hear any sound, and the COMP pot burned. I saw a red dot appear on it.

Do you have any ideas ?

[aleks_tedstone]

Check the board for solder bridges and short circuits with the continuity setting on your multimeter, especially around whenre +9V comes in. Sounds like the COMP pot drew too much current... Is your test box battery powered?

Good practise to keep everything battery powered until you have verified the circuit is operating as expected. Since COMP is connected to the emitter of both your AC128s they could also have sustained some damage too, depending what the problem was.

Once you have verified that there are no shorts, power it up (with starve at its highest setting so that the board receives +9V) and measure the voltage at each transistor.

[heyveno]

i think pots are in wrong way.

[harrisxr650]

I'm pretty sure pots are wrong. They should be mounted with their outer lugs flipped. Do you have a schematic?

[idy]

On most PCBs the pots go on the "other" side vs the components. It's a mistake some of us (me) have made. By itself, that wold not affect operation, all your pots are (supposed to be) linear, so they will just work "backwards."

That one pot is probably toast. What voltage did you feed it? Double check resistor values, especially the 47k to base of first AC128 and 5.1k to collector of second, you should be able to measure those in circuit (power off!)

Also double check for solder bridges.

[Keeb]

I have circled in red where it looks like you have a bridge and in blue where you might not have an intact trace. Check the layout and measure continuity!

[Vivek]

Ha Ha Ha

"Burning Problem!"

Good one !

[heyveno]

thx all.

I use 9v DC power for tests.



I will do all you advised me, but for now i just :

-I reverse pots and change com
-I cut the Bridge n°1
-4 is a normal bridge to ground ( i will verifiy continuity on it)

I have a very low sound level. With an audio prob I can follow the signal. all is well all along the circuit, but stopping on the collector of the second resistor ac128 and 5k1 and on the volume knob.

I also have continuity between input and ground, I tried to cut any possible bridges around input, but that I always have continuity.