[HELP] Noob working on a Doombutter - no output

[meelertime]

Hi guys. So I got rather ambitious and decided to try a Doombutter as my first build. The good news is I read up on the forums here first and built a test box to test my circuit with before finishing it. The bad news is I'm barely getting past the input before I lose all signal. Here's the rundown:

Project Name: Doombutter (w/fuzz lift)
Description of Problem: No audio once I get to the first IC.
Steps Taken: Hooked the circuit to my test box and used the audio lead to determine where the audio stops. I have not yet checked anything with the multimeter (because I'm not sure exactly how  )

I'm sure the problem could possibly be a bridge, but honestly I'm not sure how to tell that either. It doesn't look like a bridge issue to me when I look at it, but I might not be seeing what I should. I'm including some pictures as well highlighting where the signal stops (the blue circles output signal). All and any help is appreciated!

The complete photo set is in this imgur album: http://imgur.com/a/u1wTP

[jimilee]

So to check for bridges, look at the solder joints that are touching and compare it to the layout to see if those 2 points are supposed to be touching. Your soldering looks pretty good. I'd use a magnifying glass to see if each joint is soldered all the way around the lead. One or two looks like it may need touching up.

[murdog47]

Time to check voltages.Turn your multimeter on to measure voltage. Take the black probe from your multimeter and slide it in with the ground wire hooked up to your testing rig. From there, take your red probe and start checking the voltages on the ICs.

[meelertime]

Thanks for the suggestions! So to check with the meter, put the black lead to ground and then check each leg of the smaller IC?

[murdog47]

That is correct. Both IC's

[meelertime]

The voltages seem to be jumping around a lot and I'm having trouble getting a good reading; am I doing something wrong here? I shot a quick video of what it looks like.

http://youtu.be/DZWfgdefQ-A

[hammerheadmusicman]

So i'd reflow all the joints, and next to the highlighted joints, there seems to be something dicey looking between the tracks. I'd get a magnifier, and give all the track spaces a once over.

[meelertime]

Will do on the reflow; any idea why the readings jump around like that though?

[meelertime]

OK, it looks like a bad AC adapter was causing me some issues with the readings. I just tried a different adapter and I'm reading 9v at the 9v spot on the board. That being said, it doesn't look like current is passing through the diode at all. I checked for continuity and grounding and it was fine, but I don't read anything on one side of the diode. I've illustrated where I'm currently getting readings.

[jimilee]

Is that a Zener diode? Without looking at the layout, I can't tell. Also is it oriented correctly?

[meelertime]

I don't believe it's a zener diode, but I'm including some pictures for you. Also, I tried another diode with the same results.

[meelertime]

Well, after looking at the attatchment I think I see my problem. It looks like I put the diode in backwards.

[murdog47]

Diode is backwards! 

[meelertime]

LOL, I feel like an idiot! The pedal is working perfectly now!

The problem was I reversed the image of the pcb to help me trace down where the circuit path while looking at the solder side of the pcb, and I forgot that the picture of the diode is reversed. Thanks for the all the help guys, and I'm looking forward to my next build!

[murdog47]

Awesome! We've all been there!