help needed with jmk - super duper fuzz kit - no sound

[0 2339]

hi all, first time builder & poster here.

i just finished my first pedal and i've run into problems, so i'll include a link to the schematic for you:

http://jmkpcbs.com/wp-content/uploads/2016/11/Super-Duper-Fuzz.pdf

unfortunately i don't get any sound out of it. i checked all parts, orientation & wiring, made sure the board gets its voltage and the footswitch & bypass work correctly. LED is working too...

so i build myself an audio probe and started poking around and follow the audio path - turns out i don't get very far! the audio signal is lost at the 2nd leg of the R1 resistor. now if i pull out all transistors except Q1 i can follow the signal with my probe until the collector of Q2 but the moment i put in a second transistor the audio is gone. so i guess i'm loosing my signal to ground somewhere in that area... i spent hours looking around but i can't seem to figure out where it's happening.

i didn't use any substitute parts, and the only difference to the original is that the kit came with 2N3904 transistors...

if you need some photos or a list of voltages at various locations let me know and it will be here a.s.a.p.

thanks all in advance & have a nice sunday
maybe some of you can steer me in the right direction

[matmosphere]

There is a really good sticky post about what to put in tech help post, it'll help people understand the issue.

Post some clear pictures of the top and bottom of the board. Voltages at the transistor legs will probably be helpful.

But first thing I would check is make sure the pinout of the 2n3904 is the same as the original transistors. Sometimes you have to flip them.

http://beavisaudio.com/techpages/transistorpinouts/

[matmosphere]

I just looked. The pinouts are reversed.

[0 2339]

thanks a lot! so since only pin 2 & 3 are reversed i can't just flip them, right? how do i go about this??

anyway, here are some pics too... note: i already had to pull it from it's case, had it solder multiple times so it's in a bit of a rough shape loose wires you see are connected via alligator clips to their destination while testing...(taken apart for taking fotos)

[matmosphere]

thanks a lot! so since only pin 2 & 3 are reversed i can't just flip them, right? how do i go about this??

anyway, here are some pics too... note: i already had to pull it from it's case, had it solder multiple times so it's in a bit of a rough shape loose wires you see are connected via alligator clips to their destination while testing...(taken apart for taking fotos)

The pictures aren't working, but I think you can just flip them. The original says it uses 2sc828 which has an opposite pinout to the 2n3904.

The c828 seems to have a different pinout and I think that's what you saw. In that case you would have to twist the 2nd and 3rd legs, making sure they don't short out, and then put them in.

Did you socket the transistors? If not I'd put sockets in now.

[0 2339]

yea, i did put in sockets, but i already cut the transistors so bending and inserting them isn't possible. maybe i'm too braindead, but since pin 2 would be in the same spot if i'd just flip them i assume i'd run into problems according to the layouts of the transistor legs :/

edit: i just checked the pdf & build notes and it does call for 2SC828 transistors. my kit came with the 2N3904 transistors so i guess i'm screwed
2SC828   1 - emitter   2 - collector   3 - base
2N3904   1 - emitter   2 - base   3 - collector

[matmosphere]

yea, i did put in sockets, but i already cut the transistors so bending and inserting them isn't possible. maybe i'm too braindead, but since pin 2 would be in the same spot if i'd just flip them i assume i'd run into problems according to the layouts of the transistor legs :/

edit: i just checked the pdf & build notes and it does call for 2SC828 transistors. my kit came with the 2N3904 transistors so i guess i'm screwed
2SC828   1 - emitter   2 - collector   3 - base
2N3904   1 - emitter   2 - base   3 - collector

Nah you aren't screwed at all, you can just get new 2nn3904's. Where did you get the kit BTW?

[0 2339]

ordered from musikding.de. a little marking on the transistor bag would have been nice to warn about the different layout. since i would assume a pre packed kit comes with the correct parts, or at least interchangeable parts without having an issue like this... but ultimately it's my fault for not doing a proper check. still i'm pretty pissed

thanks a lot for your help mat

[matmosphere]

Where in Europe are you I probably have some spares I could send you? And don't be pissed, you always encounter these things. It's part of learning.

[0 2339]

pm sent thanks for the kind offer!!!

[jkokura]

And that's excellent customer service! Thanks for helping this fellow out Matt

Seriously tho, I appreciate it a lot.

Jacob