I Need a Fix-It Man

[PoindexterLabs]

I need to know if there is someone out there who would be willing to let me send them my SoundLab (along with that new-fangled and snazzy mini-controller) and figure out what the heck is wrong with it. I have reached the limits of my technical capabilities (my oscilloscope bite it a couple of weeks ago) and my patience.
When I first built the SoundLab, I was using batteries and would get interesting cycles of sound out of it. By all accounts it worked. I hooked it up the next day to brag to friends and got squat. I troubleshot, figured it out and got it working again (a couple of wires came loose from the back). Then I switched out the batteries for a 12V power supply and now it doesn't work at all.
No sound, just static.
I have triple checked wiring.
Checked the board for shorts.
Replaced all the IC's in case somehow the sensitive ones got zapped by some static.
In lieu of my oscilloscope, I used a simple probe rigged through my amp. I got nothing useful/helpful from it. (That said, I'm much better at diagnostics with a scope than with a jimmy-rigged probe.)
This annoys me greatly since I normally do okay with this stuff. I've been repairing and modding guitar pedals and amps for almost 5 years. However, synths are different beasts.
So, if you think of something I've missed or would be willing to let me send SoundLab and MiniController (we would obviously make some kind of financial arrangement).
Any and all input is appreciated.
Many Thanks.

[haxster]

What kind of power supply did you use, and are you using +,- 12 volts?
Are you sure u did not connect it with wrong polarity?

[ericcoleridge]

yeah man, if it was working before, and not after you changed power supply-- it would most likely figure that the power isn't connected properly-- or that something else got disconnected when you made the switch.

You could get a cheap $10 multimeter at Radio Shack and check your PS, and it's connection. Then check to see that your power rails are conducting properly to each IC. If that's all right, then start checking the audio path again. There are probably little waveforms on Ray's schematic; if you put your amp rigged probe on the those points, test for sound, you can probably isolate where your bad connection is.

In my experience, it's almost never a bad IC and usually not even other bad components. When I have problems--and I almost always do-- it's most likely a bad solder point, disconnection, inadvertent solder bridge, or mis-wiring. So, it's best to stay calm, and focused.

[Zodiak]

I use Cooledit to view waveforms, just connect my test lead to the mic/sound input, put Cooledit on pause/record and watch the waveforms

It might be worth checking your PC bundled software to see if you have anything similar.

For DC levels (and some AC) I use a multimeter.