Bumblebee Noob Problems – Help!

[GeorgeFormanGrill]

I'm looking for some sage advice debugging this bad boy. Believe it or not, despite the crappy soldering, I had this Bumblebee board working. I went back last night to test again before boxing it up and now I'm getting nothing. There's some crackling when I wipe the pots, but other than that the signal isn't coming through.

I'm hooking the board up to a text box that I built for this and future projects. The bypass switching is working fine. Does anyone have any advice? I'm including pictures of the board, pots, and the text box. Really eager to get my first project completed. Any help you all can lend is much appreciated.

https://www.dropbox.com/s/vok5xofkiyo69ez/20140204_080622.jpg
https://www.dropbox.com/s/htnf0rb47c637sw/20140204_080633.jpg
https://www.dropbox.com/s/plnj5qqarut8pit/20140204_080741.jpg
https://www.dropbox.com/s/5e3nxzez197yb0a/20140204_080758.jpg
https://www.dropbox.com/s/hao6c6gq429alnq/20140204_080823.jpg
https://www.dropbox.com/s/03o0kkt3macp9rj/20140204_080834.jpg
https://www.dropbox.com/s/1iezlu22bgar2gd/20140204_080851.jpg
https://www.dropbox.com/s/x5ctgtdn0p76yje/20140204_081403.jpg
https://www.dropbox.com/s/tao1lok3akax3vx/20140204_081409.jpg
https://www.dropbox.com/s/dnb718fflum3v9q/20140204_081416.jpg

Thanks!
George

[m-Kresol]

Hi. Congrats on your first build. So now, let's get that baby working! I don't have THE solution, but maybe some parts to check out first.

on your testing rig: The green wire should be the one connecting the Board OUT to the switch. From what I see, you just wound two wires around each other. Solder that! If it's soldered already, use more solder. Also, you want to insulate that naked wire with heatshrinking tube or electrical tape.
that could be one of the easiest fixes. The board should be okay, since you said it worked before.

Anyhow, check the following: are the potentiometer lugs connected to the correct pads on the pcb? Easy to switch 1 and 3, that was also my first mistake, but since you used 3 different colours it should be easy to check. Then check the pinout on your transistors. Depending on the type of transistor you used, the pinout can easily differ from the one that is specified on the build doc. Double check, since you handwired them to the pcb (same as with the pots basically). Also make sure that you have good contact between your wire and the sockets for the transistors. Maybe, you just got a loose contact.
hope I could be of any help

[GeorgeFormanGrill]

Right on. Thanks for the reply. Will definitely re-solder the OUT.

Pot lugs are 1-2-3 going left to right, correct?

I'm using the PNP "Continental" transistors from Smallbear (OC76). Am I correct in assuming the red dot is the collector, middle lead is base, and opposite emitter? Is there a way to use my DMM to double-check? Tried looking online before diving in and I couldn't come up with much.

Also the tab decal on the board from Madbean indicates the collector?

Thanks!
George

[Bret608]

Hey man,

It does look like you have your pots wired correctly.

On those transistors, the red dot usually means the emitter. Also, on Madbean boards, the little tab on the transistor silkscreen image means the emitter. In your pictures, it looks like they're oriented correctly, but you may want to double check. If you took them out and put them back in facing the wrong way, that could be your issue.

Let us know how it goes! 

[m-Kresol]

Usually, you can find the emitter-base-collector pin positions from the datasheet. Unfortunately, I couldn't find one for the OC76 atm. Nevertheless, Bret608 is absolutely right.
Since your effect worked before the error is most likely a short or a loose contact. One rookie mistake I made with my first build was that I shorted my board pins with the pots. Just double check your connections, especially those of the wires going into the sockets.
One more thing I just noticed: C1 and C5 are supposed to be 100nF. If I'm reading correctly on your photos, they are 1µF in your build....

[GeorgeFormanGrill]

Thanks so much for taking the time Bret608 and m-Kresol. I was told in an earlier thread that the red dot indicated collector, so I might have turned myself around. I'll test the transistors tonight to make sure I've got the pinout correct.

C1 and C5 are .1uf. That's 100nF, right?

Will report back.

[GeorgeFormanGrill]

Just to clarify, what am I looking for to avoid shorts? Solder bridges, stuff like that?

Thanks again
George

[dondougie]

On all the OC75/76/77/78's I have, the red dot indicates the collector. Looks like you just have to swap the pins. This would also explain the crackling sound when you turn the pots (been there, done that )

[m-Kresol]

Hi. Yes, 0.1uF=100nF.

Just to clarify, what am I looking for to avoid shorts? Solder bridges, stuff like that?

Yes. Just make sure there is no connection between any of your pins and that no bare wires touch anywhere.