Dandy Horse no output issues

[jwyles90]

Hey all!

I just finished up this Lectric FX Dandy Horse build and am a bit stumped by it at the moment. Hoping to get some guidance from you all, if possible. I'm running into some issues on the biasing section.

Initially, I was able to get 500hz and 125hz readings from the test pad. When I went to audioprobe test pad #3 though, I wasn't getting any kind of audio signal. I tried switching out IC 3, and realized that I had forgotten to solder BOTH jumpers into place (only had one under the chip). After installing both I'm still not getting any audio signal from the bias 2 test pad portion.

I'm not entirely sure where to go from here. It seems like there's some kind of issue with the chip, but I don't know what that would be, so any help would be greatly appreciated!

 

[jwyles90]

Update: I traced the signal with my audioprobe and seem to be hitting a dead end once I get to IC 3. The signal makes it into IC just fine at pin 3, but there's nothing coming out of pin 7 and my voltage readings are all out of whack:

1--5.3v
2--7.3v
3--4.7v
4--14.9v
5--14.9v
6--7.3v
7--9.8v
8--9.8v

 

[jimilee]

Update: I traced the signal with my audioprobe and seem to be hitting a dead end once I get to IC 3. The signal makes it into IC just fine at pin 3, but there's nothing coming out of pin 7 and my voltage readings are all out of whack:

1--5.3v
2--7.3v
3--4.7v
4--14.9v
5--14.9v
6--7.3v
7--9.8v
8--9.8v

Can you take the IC out and jump 3 to 7 and get further? It’s either that IC or something after.

 

[jwyles90]

Can you take the IC out and jump 3 to 7 and get further? It’s either that IC or something after.

Yea I'll give that a shot. I tried reflowing all the components around that IC (on the schematic) and that didn't make much of a difference. With my audio probe the signal makes it all the way to pin 3 of the chip then doesn't come back out again, and the resistor that pin 7 would be going to isn't getting a signal either.